glssr60: There appears to be 10 save slots available when I go to load but after I reached the third save slot it appears to be just overwriting that third one. There has been no forthcoming 4th, 5th, 6th, etc. saves. Any help or suggestions? Thanks.
Are you sure you are describing the problem correctly, including the right game? I am almost certain you can't choose a save-slot in MM3 except at the very beginning of a game (that is, you can only have one save slot per game).
(My memory may be fooling me and I can't check right now, though, so sorry if I am wrong.)