As a general comment, I suggest you to use the JBossWS-CXF / Apache CXF libraries that are available on AS7, instead of bundling Apache CXF 2.5.0 or Spring-WS.
This said, in order for figuring out what's happening here, you should probably try looking for the actual cause (I guess a CNFE) of the exception you posted above. I would do that by enabling TRACE level logging for the org.jboss.modules package and carefully looking at the logs just before the exceptions above first occur.