I've had this problem with two DEK Horizon 03i printers.
The first time it was the camera (firewire) causing the PC to freeze. The second time it was the firewire card in the PC that was the problem.
Try moving the camera firewire cable to a different slot on the PC (there's usually three). If that fixes the problem, even temporarily its probably the firewire card in the PC that is the problem and they are relatively inexpensive to replace.
Failing that it could be the camera or the PC at fault.