move up to jboss-3.0.4 and I will help you
I've got the same problem both with 3.03 and 3.0.4.
JSPs do not compile with both jetty and tomcat.
I found the problem... When I start JBoss with JBuilder it starts on port 8083. When I run the JSP it also tries to go to 8083. However, Jetty is listening on port 8080.
As soon as I changed the URL to http://localhost:8080/display.jsp it worked as expected.