I have the exact same issue on both my 1.85Ghz macbook pro (1st gen) and my 3.06Ghz iMac. neither using mouse nor keyboard will let me select wether to go online or not, yet I get the same roll over mouse effect you mention. Both running 10.5.2 Ah well, back to using bootcamp for it, no biggy really, just would ave been nice for quick 2 min plays.
Update: I changed my bottle to win98 (it was 2000 by defualt, and xp made no difference). I can now select buttons! However I still can't play as it won't let me go online to connect to my profile I use in bootcamp, and if I make a new profile, after entering details (the point it should go to the menu) it just quits with no message. Upon next enter the new account I made is there, but selecting it quits in the same way.