A few things.
Can you post a screenshot of the error?
Are you doing this from a remote console? If so, is it patched to the same level of the core server?
If it is failing from a remote console, does it work from the core server?
If it is failing from the remote console, make sure that the Remote Registry service is running on the core server.
I've gotten in the habit on closing any open threads to the DB3 file before trying to recreate it.