Most of you have probably upgraded to MM 4.x by now.
And that's a good thing.
During development of MMWI I've come across some unfortunate behaviour regarding the MM 3.x database.
It seems that when to change a song's rating in MM 3.x the application put a rather long-lasting lock on the database.
This means that other application cannot access the database during this period of time.
I guess MM 3.x wasn't designed to share database access.
So....if you have MMWI running and change a song's rating - regardless of it being via the MM user interface or via the MMWI (0.9.5.0+) option - you run the risk of MM locking the database indefinitely.
If MMWI queries the database while it's locked by MM 3.x's rating update method it appears that the database remaing locked requiring a forcible process exit of both MM and MMWI or a computer reboot.
You have three options