Thanks for the help everyone!. I do have one of the digi approved firewire cards (NN-440012). I did a lot of research before I switched to 7.0, I was also using the 001 and 6.4 cs9. I'm wondering now if I might have a defective firewire card?.

I too am using a DIGI quaiified rig. I used 6.9 for a long time without a hiccup on my system. 7.3 was installed and it runs pretty well but its a little suspect at time. I dont have the confidence that I did on 6.9 with a client. I think the secret might be in the busses. Not sure though. I had firewire seagates attached and disconnected them to allow more room on the Firewire bus...switching to internal secondary drives. No change.

Have you tried the steps in the thread yet? I see that your SoundBlaster card still seems to be enabled - those have been known to conflict with Pro Tools and could be part of the problem.