Problem with "save" action on objects (org.hibernate.StaleStateException)

Dear all, I've recently migrate my XWiki installation to an other server after a hard drive crash. I've copied my XWiki installation as it was and upgrade from Tomcat 5.5.15 to Tomcat 5.5.17. Tomcat is able to start correctly however the behaviour of XWiki has been affected since I can't anymore use the "save" action on an object. For instance, if I reach the "Class Editor" page (XWiki.XWikiClasses) : - click on "PhotoAlbumClass" to create a new photo album - create a new photo Album called "Photos.MyAlbum" - I can see a form but if I enter a title and a description and then I save, I get a blank page without any object attached. - I have the following errors in my logs : 10:06:59,441 ERROR TP-Processor30 http://manage.objectweb.org/xwiki/bin/save/Photos/MyAlbum AbstractBatcher:doExecuteBatch:60 - Exception executing batch: org.hibernate.StaleStateException: Batch update returned unexpected row count from update: 0 actual row count: 0 expected: 1 at org.hibernate.jdbc.BatchingBatcher.checkRowCount(BatchingBatcher.java:92) ... 10:06:59,442 ERROR TP-Processor30 http://manage.objectweb.org/xwiki/bin/save/Photos/MyAlbum AbstractFlushingEventListener:performExecutions:277 - Could not synchronize database state with session org.hibernate.StaleStateException: Batch update returned unexpected row count from update: 0 actual row count: 0 expected: 1 ... Does somebody know what is wrong is my configuration ? -- Xavier MOGHRABI - Consortium ObjectWeb Jabber: moghrabi(a)jabber.objectweb.org - Phone: +33 4 76 61 52 35