Load linkage error - "com/crystaldecisions/sdk/occa/report/data/Fields"

We had installed and were using Crystal Reports for Eclpse with JBoss 4.2. We recently upgraded to JBoss 5.1 Our crystal reports do not work from the web interface anymore. The error we get is:

Caused by: java.lang.LinkageError: loader constraint violation: loader (instance of org/jboss/web/tomcat/service/WebCtxLoader$ENCLoader) previously initiated loading for a different type with name "com/crystaldecisions/sdk/occa/report/data/Fields"

It looks like there might be a class conflict with JBoss jars? Any ideas on which jars to look at would be really appreciated. Any other ideas or suggestions on what this error might be?

Thank you.