Strange (database?) error...

I have been using an Access 97 database with a Visual Basic 6 (DAO 3.51) application over a local network with many computers accessing the database at once. I recently converted to Access 2000 (DAO 3.6) when everything went bananas. If more than one computer tries to open the database at once I get error #3734. If the computer using the database releases it, another is allowed to open it which strikes me as wierd as the database is not opened exclusively. I can't seem to find any information on this error. Perhaps the strangest thing of all is that it works on another network i tested it on. Does anyone have a clue?