I would recommend the Dir function in VBA. It is called first with the filespec you are searching (like *.rep). It is then subsequently called with just the Dir command to get the next filename, repeating your loop until the call returns an empty string (“”). Sounds exactly like what you are after.
There is an example of using the Dir function in this utility here on BOB.
Dwayne Hoffpauir 
(BOB member since 2002-09-19)