http://seamframework.org/Community/IllegalClassNameException
he Problem is related to Weld: https://issues.jboss.org/browse/WELD-897
It is fixed in the current version of weld, however the JBoss AS 6 doesn’t come with that by default.
The most trivial way, to upgrade weld is to go into your
$JBOSS_HOME/server/<whatever>/deployers/weld.deployer/
and delete the weld-core-no-jsf.jar
Then download the current weld-jar (https://repository.jboss.org/nexus/content/groups/public-jboss/org/jboss/weld/weld-core/1.1.1.Final/weld-core-1.1.1.Final.jar) and throw it into the weld.deployers directory.
At least it worked for me…
Good luck