failed to write bundle: deadbeef-cafe-babe-cafe-babecafebabe

Hello,

Yesterday when inputting data in Nuxeo our Nuxeo/JBoss server crashed. When restarting we get a 'Failed to
write bundle' exception (the full stack trace is available below).

We are using Nuxeo 5.1.5.GA. Nuxeo is connected to Oracle using the described procedure in the 'Sample
Oracle Setup' I found in VCS.

It is not the first time this problem occurs. Previously we could get away with just dropping the user and
have nuxeo recreate all content, since the database contained only test data. 

But now we are preparing the application for production and would really need a clean and reliable solution
for this problem without losing any data.

So here are my questions:
1) what happened?
2) what data got corrupted?
3) how can this be fixed without losing any data?

Thank you for any suggestions on how to solve this.

Full stack trace:
Caused by: org.nuxeo.ecm.core.api.WrappedException: Exception: java.lang.RuntimeException.
message: Failed to intialize repository: default
	at org.nuxeo.ecm.core.jca.JCAManagedConnectionFactory.getRepository(JCAManagedConnectionFactory.java:176)
	at org.nuxeo.ecm.core.jca.JCAConnectionFactory.getSession(JCAConnectionFactory.java:81)
	at org.nuxeo.ecm.core.api.ejb.DocumentManagerBean.createSession(DocumentManagerBean.java:203)
	at org.nuxeo.ecm.core.api.ejb.DocumentManagerBean.getSession(DocumentManagerBean.java:190)
	... 271 more
Caused by: org.nuxeo.ecm.core.api.WrappedException: Exception: