I think this is related to bug 3359 (undeployment does not clean up completely). When I deployed into a fresh domain I got an error message pointing to some errors in JPA validation or something similar. Deploying THE SAME application a second time brought up an error like yours or a ClassNotFoundException. Currently my workaround is a script that automatically rebuilds my domain from scratch. At the time #3359 is marked as fixed already and I hope it will be contained in the upcoming promoted build.
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