MSACCESS native applications make use of the Microsoft JET database native driver, which is not directly supported by LoadRunner. Why? Microsoft Access applications generally cap out in the 6-10 user range, which can effectively be tested by hand.
If your application makes use of a non-native interface (i.e. not Jet) to get to the MSACCESS application then you are looking likely at ODBC or OLEDB (DCOM) for your access. You can also take VB or C source code and "roll your own" as a DLL-Style virtual user.