I purchased a 80GB PS3 and when attempting to play Gauntlet, a PS2 game, I received an error message stating that the system was not compatible with PS2 games. How can that be? According to the list, I should have no problems playing this game on a 80GB PS3.
Unfortunately you have one of the PS3's without PS2 backward compatibility at all. First PS3's (20GB and 60GB) had it, and AFAIK some 80GB's have it, the newer ones, do not.
There have been rumors, that Sony might add PS2 compatibility via the PSN Store, however if or when that happens, is unknown.