It looks like you're experiencing a more serious kernel panic. You need to start eliminating variables. First, disconnect non-essentially peripherals and see if the problem continues. If it does, I would next run the Hardware Test CD. If it passes but the panics continue, the next thing I'd suggest would be to pull out additional RAM you've installed. If it persists, do an Archive and Install of OS X. If the problem persists even then, try a different hard drive. And if all of that does not work, it's time to seek hardware help.