[xwiki-users] Error while importing .xar

Hi During import of a Backup.xar, I got the following error: Error number 4001 in 4: Error while parsing velocity page Wrapped Exception: Invocation of method 'getAttachmentRevision' in class com.xpn.xwiki.api.Attachment threw exception com.xpn.xwiki.XWikiException: Error number 3004 in 3: Exception while manipulating the archive for file Backup.xar Wrapped Exception: Error number 3231 in 3: Exception while loading attachment Backup.xar of document XWiki.Import Wrapped Exception: exception setting property value with CGLIB (set hibernate.cglib.use_reflection_optimizer=false for more info) setter of com.xpn.xwiki.doc.XWikiAttachmentArchive.setArchive @ [16,31] What do I have to do to fix it? I need to migrate an existing XWiki installation to another server and database. I already tried moving the database directly, but since I use two different rdbms', this gives me errors as well. Thanks, Tobias