I start JBoss and try to access the jmx-console and get:

HTTP Status 500, where the exception says org.apache.jasper.JasperException: Unable to compile class for JSP.

Check to make sure that you have an environment variable JAVA_HOME set to a full JDK install (pointing to the root install directlory). 

Also, check that you don't have a jar file available in your jre/lib/ext which provides a servlet/JSP api. This can cause incompatibility with the api provided by jboss and can render the pages of jboss unusable.

Also, the reason for the following error

+org.apache.jasper.JasperException: Unable to compile class for JSP

Generated servlet error:

The code of method _jspService(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) is exceeding the 65535 bytes limit+

could be a bug with tomcat as mentioned here at: http://mail-archives.apache.org/mod_mbox/tomcat-dev/200604.mbox/%3Cbug-39309-78@http.issues.apache.org/bugzilla/%3E