Have a look at the resulting connection string - which should look like this
Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Mybase.mdb;Jet OLEDB:System Database=C:\MySysBase.mdw;User ID=Admin;Password=*;
I.e. without the "Jet OLEDB:" bit on the password. See reference
Access connection strings - ConnectionStrings.com[
^]
BTW It's very unusual to store files in the root folder of C: - I strongly advise you to use a specific folder, or ProgramData folder etc.