What was the exception? Are there any stray jar files in the endorsed directory? You could try adding -verbose:class to the Java command that starts Ant, this should point out if stray jars are being picked up. I once spent days debugging a issue where suddenly the JBossAS build would stop working on a certain computer, giving a missing method error when I could see that method in the .java source file. Apparently someone in some other department was too lazy to properly set up the classpath for his build, so his build script copied an older version of a JBoss jar file into the endorsed directory. The first time he did his build on that common build machine, my build stopped working. Eventually, I ran out of common build machines and I was forced to solve the problem; -verbose:class pointed out the culprit. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4036763#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...