I attempted to see if there where any entries on the P4 beta tester database on this but the server is down. Probably as a result of all the stuff going on at Meta. If I remember correctly, there where some issues about graphics card drivers and the amount to memory. If you haven't done it already, you might want to is if there are any updated drivers for your graphics card. The memory issues where directed more to the PC side then the MAC side. This is on a PC right? If so, how much memory do you have in it. I have heard other folks have had problems if they are close to the system requirements for P4. I'll keep checking on the database to see if comes back up till then there's not much more I can tell you on this.