Just wondering whether you were able to find a solution to this very frustrating problem?
Any help would be greatly appreciated!
Not sure if this will be any help to anyone but...
The problem occurs when using the commons-logging.jar package inside a web application deployed on JBoss 3.2.5 (or higher).
The latest JBoss uses Tomcat 5.X and evidently there is a class loading issue with this (there are other posts with the details). So basically just remove the commons logging jar file from the deployed package and things will work.