Just installed a propper licence on previously evaluation server and this started happening on the issues page. I've updated to 5.1.2, updated all the plugins, still I get this crippling error message where the comments/activity details used to be.
activitymodule
Error rendering 'com.atlassian.jira.jira-view-issue-plugin:activitymodule'. Please contact your JIRA administrators.

This is what I get in the log file (note, we don't use stash so perhaps that's a clue)...
2012-08-15 15:13:02,518 http-8080-14 ERROR username 913x2645x1 1jvx6w9 x.x.x.x,x.x.x.x /browse/CID-6 [jira.web.component.ModuleWebComponentImpl] Error rendering web panel: com.atlassian.jira.jira-view-issue-plugin:activitymodule (null)
java.lang.NoClassDefFoundError: com/atlassian/applinks/api/application/stash/StashApplicationType
at com.atlassian.jirafisheyeplugin.stash.StashCommitServiceImpl.isConfigured(StashCommitServiceImpl.java:160)
at com.atlassian.jirafisheyeplugin.web.issuetabpanel.fisheye.FishEyeIssueTabPanel.isShowPanel(FishEyeIssueTabPanel.java:362)
at com.atlassian.jirafisheyeplugin.web.issuetabpanel.AbstractFishEyeCrucibleIssueTabPanel.showPanel(AbstractFishEyeCrucibleIssueTabPanel.java:75)
at com.atlassian.jira.plugin.issuetabpanel.IssueTabPanelInvokerImpl.invokeShowPanel(IssueTabPanelInvokerImpl.java:42)
at sun.reflect.GeneratedMethodAccessor336.invoke(Unknown Source) <+1>
at java.lang.reflect.Method.invoke(Unknown Source)
at com.atlassian.multitenant.impl.MultiTenantComponentFactoryImpl$AbstractMultiTenantAwareInvocationHandler.invokeInternal(MultiTenantComponentFactoryImpl.java:181)
at com.atlassian.multitenant.impl.MultiTenantComponentFactoryImpl$MultiTenantAwareInvocationHandler.invoke(MultiTenantComponentFactoryImpl.java:211)
at $Proxy244.invokeShowPanel(Unknown Source) <+2>
at java.lang.reflect.Method.invoke(Unknown Source)
at com.atlassian.plugin.osgi.hostcomponents.impl.DefaultComponentRegistrar$ContextClassLoaderSettingInvocationHandler.invoke(DefaultComponentRegistrar.java:129)
at $Proxy244.invokeShowPanel(Unknown Source) <+2>
at java.lang.reflect.Method.invoke(Unknown Source)
at com.atlassian.plugin.osgi.bridge.external.HostComponentFactoryBean$DynamicServiceInvocationHandler.invoke(HostComponentFactoryBean.java:154)
at $Proxy244.invokeShowPanel(Unknown Source)
at com.atlassian.jira.plugin.viewissue.ActivityBlockViewIssueContextProvider.getTabPanels(ActivityBlockViewIssueContextProvider.java:194)
at com.atlassian.jira.plugin.viewissue.ActivityBlockViewIssueContextProvider.getContextMap(ActivityBlockViewIssueContextProvider.java:74)
at com.atlassian.jira.plugin.webfragment.CacheableContextProviderDecorator.initContextMap(CacheableContextProviderDecorator.java:70)
at com.atlassian.jira.plugin.webfragment.CacheableContextProviderDecorator.getContextMap(CacheableContextProviderDecorator.java:46)
at com.atlassian.jira.plugin.webfragment.contextproviders.MultiContextProvider.getContextMap(MultiContextProvider.java:99)
at com.atlassian.plugin.web.descriptors.DefaultWebPanelModuleDescriptor$ContextAwareWebPanel.getHtml(DefaultWebPanelModuleDescriptor.java:143)
at com.atlassian.jira.web.component.ModuleWebComponentImpl.renderModule(ModuleWebComponentImpl.java:84)
at com.atlassian.jira.web.component.ModuleWebComponentImpl.renderModuleAndLetNoThrowablesEscape(ModuleWebComponentImpl.java:67)
at com.atlassian.jira.web.component.ModuleWebComponentImpl.renderModules(ModuleWebComponentImpl.java:45)
at com.atlassian.jira.issue.util.IssueWebPanelRenderUtil.renderPanels(IssueWebPanelRenderUtil.java:80) <+2>
at java.lang.reflect.Method.invoke(Unknown Source)
at webwork.util.InjectionUtils$DefaultInjectionImpl.invoke(InjectionUtils.java:70)
at webwork.util.InjectionUtils.invoke(InjectionUtils.java:56)
at webwork.util.ValueStack.findValue(ValueStack.java:514)
at webwork.util.ValueStack.findValue(ValueStack.java:213)
at webwork.view.taglib.WebWorkBodyTagSupport.findValue(WebWorkBodyTagSupport.java:62)
at webwork.view.taglib.BasicPropertyTag.doStartTag(BasicPropertyTag.java:54)
at org.apache.jsp.secure.views.issue.viewissue_jsp._jspx_meth_ww_005fproperty_005f4(viewissue_jsp.java:546)
at org.apache.jsp.secure.views.issue.viewissue_jsp._jspx_meth_ww_005fproperty_005f3(viewissue_jsp.java:514)
at org.apache.jsp.secure.views.issue.viewissue_jsp._jspService(viewissue_jsp.java:163)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:386)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) <+4> (ApplicationFilterChain.java:290) (ApplicationFilterChain.java:206) (IteratingFilterChain.java:46) (DelegatingPluginFilter.java:66)
at com.atlassian.labs.botkiller.BotKillerFilter.doFilter(BotKillerFilter.java:30) <+46> (DelegatingPluginFilter.java:74) (IteratingFilterChain.java:42) (DelegatingPluginFilter.java:66) (ContextFilter.java:25) (DelegatingPluginFilter.java:74) (IteratingFilterChain.java:42) (ServletFilterModuleContainerFilter.java:77) (ServletFilterModuleContainerFilter.java:63) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (SiteMeshFilter.java:59) (SitemeshPageFilter.java:124) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (IteratingFilterChain.java:46) (ServletFilterModuleContainerFilter.java:77) (ServletFilterModuleContainerFilter.java:63) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (SecurityFilter.java:82) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (BaseLoginFilter.java:157) (JiraLoginFilter.java:70) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (IteratingFilterChain.java:46) (DelegatingPluginFilter.java:66) (OAuthFilter.java:71) (DelegatingPluginFilter.java:74) (IteratingFilterChain.java:42) (ServletFilterModuleContainerFilter.java:77) (ServletFilterModuleContainerFilter.java:63) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (IteratingFilterChain.java:46) (ServletFilterModuleContainerFilter.java:77) (ServletFilterModuleContainerFilter.java:63) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (ApplicationDispatcher.java:646) (ApplicationDispatcher.java:436) (ApplicationDispatcher.java:374) (ApplicationDispatcher.java:302) (JiraWebworkActionDispatcher.java:314) (JiraWebworkActionDispatcher.java:205)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) <+4> (ApplicationFilterChain.java:290) (ApplicationFilterChain.java:206) (IteratingFilterChain.java:46) (DelegatingPluginFilter.java:66)
at com.atlassian.labs.botkiller.BotKillerFilter.doFilter(BotKillerFilter.java:30) <+40> (DelegatingPluginFilter.java:74) (IteratingFilterChain.java:42) (DelegatingPluginFilter.java:66) (ContextFilter.java:25) (DelegatingPluginFilter.java:74) (IteratingFilterChain.java:42) (ServletFilterModuleContainerFilter.java:77) (ServletFilterModuleContainerFilter.java:63) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (IteratingFilterChain.java:46) (ServletFilterModuleContainerFilter.java:77) (ServletFilterModuleContainerFilter.java:63) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (SecurityFilter.java:82) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (BaseLoginFilter.java:157) (JiraLoginFilter.java:70) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (IteratingFilterChain.java:46) (DelegatingPluginFilter.java:66) (OAuthFilter.java:71) (DelegatingPluginFilter.java:74) (IteratingFilterChain.java:42) (ServletFilterModuleContainerFilter.java:77) (ServletFilterModuleContainerFilter.java:63) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (IteratingFilterChain.java:46) (ServletFilterModuleContainerFilter.java:77) (ServletFilterModuleContainerFilter.java:63) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (ApplicationDispatcher.java:646) (ApplicationDispatcher.java:436) (ApplicationDispatcher.java:374) (ApplicationDispatcher.java:302)
at com.atlassian.jira.servlet.QuickLinkServlet.linkToIssue(QuickLinkServlet.java:158)
at com.atlassian.jira.servlet.QuickLinkServlet.service(QuickLinkServlet.java:46)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) <+10> (ApplicationFilterChain.java:290) (ApplicationFilterChain.java:206) (ChainedFilterStepRunner.java:78) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (HeaderSanitisingFilter.java:44) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (IteratingFilterChain.java:46) (DelegatingPluginFilter.java:66)
at com.atlassian.labs.botkiller.BotKillerFilter.doFilter(BotKillerFilter.java:36) <+3> (DelegatingPluginFilter.java:74) (IteratingFilterChain.java:42) (DelegatingPluginFilter.java:66)
at com.atlassian.jira.tzdetect.IncludeResourcesFilter.doFilter(IncludeResourcesFilter.java:39) <+24> (DelegatingPluginFilter.java:74) (IteratingFilterChain.java:42) (DelegatingPluginFilter.java:66) (ContextFilter.java:25) (DelegatingPluginFilter.java:74) (IteratingFilterChain.java:42) (ServletFilterModuleContainerFilter.java:77) (ServletFilterModuleContainerFilter.java:63) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (AccessLogFilter.java:103) (AccessLogFilter.java:87) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (XsrfTokenAdditionRequestFilter.java:54) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (SiteMeshFilter.java:129) (SiteMeshFilter.java:77) (SitemeshPageFilter.java:124) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (IteratingFilterChain.java:46) (DelegatingPluginFilter.java:66)
at com.atlassian.labs.remoteapps.modules.permissions.ApiScopingFilter.doFilter(ApiScopingFilter.java:71) <+41> (DelegatingPluginFilter.java:74) (IteratingFilterChain.java:42) (ServletFilterModuleContainerFilter.java:77) (ServletFilterModuleContainerFilter.java:63) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (SecurityFilter.java:234) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (TrustedApplicationsFilter.java:98) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (BaseLoginFilter.java:157) (JiraLoginFilter.java:70) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (IteratingFilterChain.java:46) (DelegatingPluginFilter.java:66) (OAuthFilter.java:71) (DelegatingPluginFilter.java:74) (IteratingFilterChain.java:42) (ServletFilterModuleContainerFilter.java:77) (ServletFilterModuleContainerFilter.java:63) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (ProfilingFilter.java:99) (JIRAProfilingFilter.java:19) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (AbstractJohnsonFilter.java:71) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (UrlRewriteFilter.java:738) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (GzipFilter.java:74) (GzipFilter.java:51) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (IteratingFilterChain.java:46) (DelegatingPluginFilter.java:66)
at com.atlassian.labs.remoteapps.modules.oauth.OAuth2LOFilter.doFilter(OAuth2LOFilter.java:70) <+47> (DelegatingPluginFilter.java:74) (IteratingFilterChain.java:42) (DelegatingPluginFilter.java:66) (JWDSendRedirectFilter.java:25) (DelegatingPluginFilter.java:74) (IteratingFilterChain.java:42) (ServletFilterModuleContainerFilter.java:77) (ServletFilterModuleContainerFilter.java:63) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (ChainedFilterStepRunner.java:78) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (AbstractCachingFilter.java:33) (AbstractHttpFilter.java:31) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (AbstractEncodingFilter.java:41) (AbstractHttpFilter.java:31) (PathMatchingEncodingFilter.java:49) (AbstractHttpFilter.java:31) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (ActiveRequestsFilter.java:346) (ActiveRequestsFilter.java:463) (ActiveRequestsFilter.java:173) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (JiraStartupChecklistFilter.java:75) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (MultiTenantServletFilter.java:91) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (ChainedFilterStepRunner.java:78) (ApplicationFilterChain.java:235) (ApplicationFilterChain.java:206) (StandardWrapperValve.java:233) (StandardContextValve.java:191) (StandardHostValve.java:127) (ErrorReportValve.java:102) (StandardEngineValve.java:109) (AccessLogValve.java:554) (CoyoteAdapter.java:298) (Http11Processor.java:859) (Http11Protocol.java:588) (JIoEndpoint.java:489)
at java.lang.Thread.run(Unknown Source)