Been running Mnemosyne on Windows Xp for some time without any problems.
Yesterday I decided to do a fresh install of Winxp and after installing mnemosyne, found I was unable load 'Browse Cards' and encountered the 'Database error, Driver not loaded Driver not loaded' message then the crash.
Also, image files would not show unless I converted them {jpg} to png and then edit the entry.
Anyway to cut to the chase I decided to instal Netframework 1-4, and it was after I had installed versions 3.5 and 4.0 which require reboot, that Mnemosyne was once again fully functional. How lucky was that!
Hope this is of some help to other windows users.