Thank you so much, I finally got it to work. My mining speed is currently about 40 Mhash/s, and as far as I know, that's not very good. Any idea how I can get a better speed? I also keep getting these "Block x found on ATI Radeon HD 5670 (#1)". I suppose that doesn't mean I've actually found a block, as I've gotten 7 of them already - the last two with a three second interval. I'm mining as a part of the Eligius pool atm, if that has anything to say. Also, my usually überfast Mac got reeeeally slow now, but I guess that's a prize I have to pay for mining Bitcoins.

EDIT: One more noob-question: How do I quit DiabloMiner? By quitting Terminal?