I suspect that you are running with Jetty3 when you need Jetty4.
JBoss CVS HEAD and Branch_3_0 (tag) both now contain Jetty4.
I would check out Branch_3_0 - it's pretty robust and try it in that.
Go to www.sf.net, search for the JBoss project, go to the cvs page and follow the checkout instructions (don't forget you need to specify the tag Branch_3_0).
cd build/ and run build.sh/bat. the result goes into build/output/
thank you for the suggestion, I will give it a try!