I had the same problem and discovered that it is the unusual mainfest data in jdom.jar
probably located in WEB-INF/lib that causes the problem.
I removed the manifest and info.xml from the META-INF inside the jdom.jar and it solved the problem.

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Helge Tesgaard
IT Consultant/Developer
PwC Consulting
P: +45 39 45 97 87  M: +45 23 73 21 43
hte@pwcconsulting.dk
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