Something is interfering with the normal compact and repair process. Access
first creates a new database named something like DB1.mdb. Then it imports
everything from the original database into it and checks it for errors. Next
it deletes the original database. After that Access copies the DB1.mdb with
the original database's name. Lastly Access deletes the DB1.mdb file.

That way there should be at least one copy of the database at all times if
something happens like a power failure.

The first thing that I'd check would be if you have read, write, create, and
delete (or modify) permissions to the folder holding the database. Not just
the file but the entire folder. If you don't have delete privs, that would
explain the DB1.mdb files.

If that isn't the problem, there might be something wrong with your database
that compact and repair won't fix. Do a Google search for the JetComp.exe
utility. It's a much better way of compacting and repairing a database and it
forces you to create a backup copy first.