Ok, Thanks for your comments, it did help me in finding out what happened. Yes, the xercesImpl.jar isn't properly loaded and the reason was because I launched the application from Ant, and Ant uses its own XML parser, which was conflicting the ones used by JBoss MC. When I manually start it then it works ok (or at least it gets futher ;-) but I will post that onto a different thread unless it appears to be a library problem). I am also thinking I will try and check if I could change the bootstrap classloader code to see if it could isolate itself from any environment it is started from (defining the parent CL as null)... Thanks again for your help. Gilles. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4036733#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...