Please Help! Unknown Bug, havnt solved yet!

Hello, i found this bug for pcs and Vista, but i am rinning on a mac. Whenever i try to go to battle.net, it says i d not have sufficient space on my harddraive do dl a file from bnet. I have alot of room on my hard drive. I know this is an existing error for pcs, but i am on a mac. What should i do? I love this game, and have reinstalled it two times, but nothing worked! HELP!!!