Is yours posi drive or not? If it is a posi drive, it will look much different than the ones I post; also, the drive you bought will not fit it. Of course, you can beat it in; after all, that's the way anyone else does who isn't familiar with standard size American fasteners.
Have you even tried a #4 Phillips bit, one that goes on the end of a 3/8 ratchet drive? Either way, chances are that you will have to drill at least one if not all of them out.