See information here:

http://forums.atlassian.com/thread.jspa?threadID=5298&tstart=0

java.lang.ClassNotFoundException: No ClassLoaders found for:
com.opensymphony.module.user.authenticator.SmartAuthenticator
at org.jboss.mx.loading.LoadMgr3.beginLoadTask(LoadMgr3.java:161)
at
org.jboss.mx.loading.UnifiedClassLoader3.loadClassImpl(UnifiedClassLoade
r3.java:169)

It appears that this is an osuser problem that has been fixed in CVS.

Whilst we are at it, we should go through and check that Class.forName() is not used in any os component.