I am having an issue were the JIRA Issues macro in an upgraded Confluence (3.1.2 -> 3.5.5) no longer displays issues. Instead we have the following. Both the JIRA and Confluence servers are setup as trusted applicaitons of each other.
Could not load org.apache.xerces.parsers.SAXParser: SAX2 driver class org.apache.xerces.parsers.SAXParser not found: org.apache.xerces.parsers.SAXParser<br/>class java.io.IOException