Furthermore, check if the JBossWS framework is already deployed (jbossws.sar directory in the JBoss deployment directory) and try to remove it. It contains already a lot of APIs and implementations that can confict with APIs and implementations provided with CXF.
Concrete example – I was using CXF 2.0 series which implements JAX-WS 2.0 standard. JBossWS 2.0 framework, shipped with JBoss 4.2, implements JAX-WS 2.1 specification. In some situations when a
dateTime was parsed I was getting
NullPointerException with a message about marshalling error. Removing the jbossws.sar helped.