Script fails to execute after upgrade of Jira from 7 to 8

[LoupGarou]

We have a script that has been working up until we upgraded the JIRA server from 7 to 8.

We are seeing the following error in the atlassian-jira.log:

"Script function failed on event: com.atlassian.jira.event.issue.IssueEvent, file: null groovy.lang.MissingMethodException: No signature of method: com.onresolve.scriptrunner.canned.jira.workflow.listeners.XXXXListener.main() is applicable for argument types: ([Ljava.lang.String;) values: [[]] Possible solutions: wait(), wait(long)...."

Snippet of code:

class XXXXListener extends AbstractIssueEventListener {

   private static final Logger LOG = Logger.getLogger(XXXXListener.class)

   @Override
   void workflowEvent(IssueEvent event) {
      LOG.debug ("Event: ${event.getEventTypeId()} fired for ${event.issue} and caught by " + this.class.getName())   

      try{}

      catch{}

      finally{}

   }

}

I have attempted removing the listener and readding with no success. I keep getting the same error in the log file. Again, this was working fine until we upgraded. Shouldn't have had to make any changes.

Thanks in advance.