Two possibilities: 1. You have a wrong/defective database driver (64-bit/32-bit) 2. Your database is corrupted.
Was XMM working before? What did you change since the last successful use of XMM? Can you create a new empty database or can you open the example database? Can you open your database file with Access, OpenOffice, etc.?
In order to achieve what is possible, you have to try the impossible over and over again. Hermann Hesse