It looks as though you were trying (in your code somewhere) to reference a table called MSysDb. This table is not an access table, so it must have been created by the person who initially implemented your database, and has been misplaced. Try holding down the shift key before and during starting-up the database. This bypasses any startup settings, so no code will be run. If the system starts up fine - ie without the error, then you know its in the code somewhere. If that is the case, go into the VB code and do a search on the whole project for the word MSysDb. If you find it, you will be one step wiser. It may then be worth working out why this table is referenced.
Please let me know if this helps.
Mr Big.