Is there any reason Worms 4 wasn't released for the American Ps2? I was considering buying it from England before I realized I would have to Mod my Ps2 in order to make the game work. Is there any other solution? If a version was released for the American Ps2 I would buy it, In fact lack of compatibility is the only reason I'm not playing this game right now.

Can't you buy it for your PC? That's what I'd recommend you anyway, the PC version is three times better.