[Microsoft][ODBC Microsoft Access Driver] '(unknown)' is not a valid path. Make sure that the path name is spelled correctly and that you are connected to the server on which the file resides.

This means there is most likely a problem with the "ConnectionString" info that you specified.

If you are using a DSN-Less Connection with MSACCESS.

Check that the physical path to the database has been specified correctly.
It has to be perfect and correct. It cannot be specified using "http://" or by using "server.mappath".
It has to be specified like the following example.

ConnectionString = "DBQ=C:\Inetpub\wwwroot\advpass_pro\_database\passwords.mdb;Driver={Microsoft Access Driver (*.mdb)};UID=admin;PASSWORD=Xpass"

If this is running on an NT server or Win2000 Server make sure that permissions have been set on the database.
Only the server admins can do this. If you are not the admin you will have to ask for this to be done.

If you are using a System DSN

It is not set up correctly. Again, make sure the permissions have been set for the database and that the system DSN has been set up correctly by the server admins.