[JBOSS6] DuplicateClass when starting JBoss 6.1 with a WAR / EAR containings struts 2 & tiles application

Based on the provided attached sample, if I put the war file on my deploy directory, start the server and try to redeploy the war I've got lot of Linkage errors for nearly all the class files used :

<<
2011-11-22 20:06:07,850 WARN [org.jboss.detailed.classloader.ClassLoaderManager] (HDScanner) Unexpected error during load of:org.apache.commons.digester.RegexMatcher: java.lang.LinkageError: loader (instance of org/jboss/classloader/spi/base/BaseClassLoader): attempted duplicate class definition for name: "org/apache/commons/digester/RegexMatcher"
at java.lang.ClassLoader.defineClass1(Native Method) [:1.6.0_21]
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632) [:1.6.0_21]
at java.lang.ClassLoader.defineClass(ClassLoader.java:616) [:1.6.0_21]
at org.jboss.classloader.spi.base.BaseClassLoader.access$200(BaseClassLoader.java:52) [jboss-classloader.jar:2.2.1.GA]
at org.jboss.classloader.spi.base.BaseClassLoader$2.run(BaseClassLoader.java:650) [jboss-classloader.jar:2.2.1.GA]
at org.jboss.classloader.spi.base.BaseClassLoader$2.run(BaseClassLoader.java:609) [jboss-classloader.jar:2.2.1.GA]
at java.security.AccessController.doPrivileged(Native Method) [:1.6.0_21]
..
>>

If I start JBoss without the war and then try to deploy it many time it doesn't fail, however as soon that the server start with the war, the linkage errors come.

Is it a bug or a misconfiguration of my war ?

Regards,
Blured.