I'm having this same problem, however removing jars from jboss/lib/endorsed is not an option. What to do then? In other forums I've seen advice to add a jboss-web.xml to my WEB-INF folder, with contents:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE jboss-web PUBLIC
"-//JBoss//DTD Web Application 4.2//EN"
"http://www.jboss.org/j2ee/dtd/jboss-web_4_2.dtd">
<jboss-web>
<class-loading java2ClassLoadingCompliance="false">
<loader-repository>
myapp:loader=anyUniqueName
<loader-repository-config>java2ParentDelegation=false</loader-repository-config>
</loader-repository>
</class-loading>
</jboss-web>
but that doesn't work either. I see no other solutions posted. Is there a way to fix this?