The classpath is definitely too long. Try setting Jasper to compile the JSP internally - that is not to fork. You will need to add it to server/default/deploy/jbossweb-jetty.sar/webdefault.xml for Jetty or server/default/deploy/jbossweb-tomcat41.sar/web.xml for Tomcat. This applies to the Jasper section of the aforementioned configuration files.
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More information here:
This should stop the system having to pass the classpath externally, which is where the problem is occurring. The drawback is that there is a chance of a crash if there is a memory leak in javac. Shouldn't be the case for Java JDK 1.4.2 but YMMV.
Hope it helps.