H/W buffer size problem with pro tools 7 (Mac OSX)

[Scprogram18]

I have been having problems with my pro tools 7 upgrade in which the H/W buffer size message constantly pops up (-9136). I only had 15 audio tracks and not one plug in was being used as of yet. I just downloaded this upgrade over the weekend and I haven't been able to get anything done since.

I decided to see if I deleted some tracks, the same thing would happen. I went down to 5 audio tracks and STILL went through the same ordeal. It's very frustrating because I can barely get by with recording, and bouncing to disk is impossible. What could possibly be wrong that it's constantly doing this?

I'm running pro tools on a Dual 2.3 GHz G5 PowerMac with OSX tiger (10.4). I don't think I should be encountering a H/W buffer size problem when I dont have that much going on with a session. Even my laptop can handle a lot more than my PowerMac was handling. Please help, I need to record. NEED.

[jes]

which interface are you using? many of us have these problems using the new firewire mbox 2 pro...

[Scprogram18]

I'm using Pro Tools 7.3 on Mac OSX Tiger with the Focusrite/Digidesign Mbox preamp.