My Linux firewall computer has to be rebooted hourly at least because of the error: kernel panic: fatal exception in inturrupt. In inturrupt handler - not syncing. The last time the message Bad EIP value preceeded this message.

I'm not familiar yet with Linux, so I may have a lot to learn.

In my experience, the most common cause of Interrupt Handler failure is a hardware problem. It may be overheating due to a failed fan, failed (bulging) capacitors on the motherboard, or a failing expansion card. Interrupt Handlers are the routines called when a physical device uses its IRQ line to notify the CPU that it needs attention. IRQs are handed out to video cards, NICs, disk/usb/firewire controllers, etc. during the POST and boot processes. An overheating or failing device can cause electrical surges, among other things, on the computer's system, memory, and IO buses, essentially drowning out the real signals, and causing the CPU to have no alternative but to halt. The indicator of the system running a hour, then panicking, suggests a device takes about an hour to overheat.

Usually EIP is indeed related to hardware ... especially bad RAM. I would run memtest86 just to make sure.