Seems like you're really suffering from the issue which has been fixed post RC4
Try the attached ones, but only to scan the shares please.
It may have unexpected side effects to the rest of the system. so please restor the prtiginal versions after the scan.
check, if the thumbs folder contains cover art then and please post configuration.log, if you still have troubles
Musicdatabasereorg: 8264 skipped because of creation before the last import