Pro Tools 7 & Application Switching, PT7 won't play after switching apps Options

[aleman]

I'm running Pro Tools 7.0 on Tiger (10.4.3) on a mirror-drive G4 with dual 1.25 Gig processors and 512 MB of RAM. For the most part PT7 runs beautifully.

The problem I have occurs when I'm running PT7 and then switch to another application (like my internet browser, or iTunes for example). When I switch *back* to Pro Tools after using the other application, I can't play my file anymore. Any attempt to hit the "play" button (either using the spacebar or my mouse) fails.

The "play" button gets highlighted for a split second, and then the "stop" button gets highlighted immediate afterwards and PT won't play. I don't get any error messages.

It's worth noting that this does NOT happen when I switch back and forth between Reason Adapted and ProTools. It's only with my other apps.

Anyone else experience this, or have an idea what's causing it?

Thanks in advance.

[aleman]

UPDATE:

So I just experienced this problem while I was still in ProTools... suddenly it wouldn't let me play back the tracks anymore. The only fix is to close the open session in ProTools, close the session in Reason, and then open it up again. Sometimes that doesn't even work and I need to quit ProTools altogether.

This leads me to believe that it's a problem with not enough CPU processing power, or some other error where ProTools doesn't have the resources it needs to play back the tracks.

It's worth mentioning that the session I was running only had three instrument tracks (all with sampling software plugins in them - 2 Sampletank, and 1 Reason instrument) and a master track. And I was only running iTunes and my internet browser (Camino) in the background.

Strange....