Comment 8 for bug 48282

If you still have an NFS filesystem try using the mount option nolock. This will lead to loclal locks only, so be sure to not work from two machines at the same time. I do not know if CIFS knows this option too.
Another option would be to move the database to a local filesystem (your home) and do an symbolic link. In this case the data is only available on one machine and has to be synced by you somehow.

This problem was discussed several times on the digicam mailinglist.
See also the digikam FAQ: http://www.digikam.org/?q=node/219