A number of people have mentioned this problem recently. I just stumbled on the following link which purports to fix the problem. I hope it's of some help.
For those who think Martin and myself go over the top with our Mozilla hype, please don't make any judgments until you've tried it. Even if you're not a geek, you'll be amazed how much better it is than IE.
well, i'm certainly wouldnt call meself a geek. but i dont see how mozilla is better. its ****ing slower, i hate it (not mozilla itself, just the fact that its slower).