When using exploded EAR/WAR deployment web.xml is modified on each server start. That has two effects:

• the original web.xml, which was renamed to web.xml.org after 1st start is lost on 2nd server start
• the context parameter jbossws.cxf.beans.url is added to web.xml multiple times

My web.xml on second server start:

<web-app>
...
<context-param>
<param-name>jbossws.cxf.beans.url</param-name>
<param-value>file:/D:/Tools/jboss-4.2.3.GA/server/default/tmp/jbossws/jbossws-cxf29799.xml</param-value>
</context-param>
<context-param>
<param-name>jbossws.cxf.beans.url</param-name>
<param-value>file:/D:/Tools/jboss-4.2.3.GA/server/default/tmp/jbossws/jbossws-cxf58750.xml</param-value>
</context-param>
</web-app>

The exception is:
...
Caused by: java.lang.IllegalArgumentException: Duplicate context initialization parameter jbossws.cxf.beans.url
at org.apache.catalina.core.StandardContext.addParameter(StandardContext.java:2332)