Strat-O-Gems - bottom of screen runoff...?

Hello!  I'm wondering - I just downloaded the rom for Strat-O-Gems onto my Harmony SD, and tried playing it... the bottom of the screen runs off my TV, so that I can't see the bottom layer of gems when I play.  Anyone have any ideas about why this might be happening?  I don't have the same problem with any other game (for example, when I go from room to room in Adventure, the bottom of the screen is exactly where it should be).

btw, sorry if there's a specific subforum for this kind of question - I'm a noob, and couldn't figure out what subforum this question would belong in...