Help with an error

Hey all,

I've got an RH server which is crashing, at random, and I hoped you all might be willing to help. It's kernel 2.4.20-19.7, and I am seeing (invar-log-messages):

Sep 15 17:35:00 si-server kernel: Unable to handle kernel NULL pointer dereference at virtual address 00000004 Sep 15 17:35:00 si-server kernel: printing eip: Sep 15 17:35:00 si-server kernel: c014edf4 Sep 15 17:35:00 si-server kernel: *pde = 00000000 Sep 15 17:35:00 si-server kernel: Oops: 0002 Sep 15 17:35:00 si-server kernel: agpgart autofs 8139too mii ipchains ide-scsi scsimod ide-cd cdrom usb-ohci usbcore ext3 jbd Sep 15 17:35:00 si-server kernel: CPU: 0 tainted Sep 15 17:35:00 si-server kernel: EFLAGS: 00010286 Sep 15 17:35:00 si-server kernel: Sep 15 17:35:00 si-server kernel: EIP is at dinstantiate kernel 0x24 (2.4.20-19.7) Sep 15 17:35:00 si-server kernel: eax: 00000000 ebx: dbd46fc0 ecx: db9b0ed0 edx: dbd46fd0 Sep 15 17:35:00 si-server kernel: esi: db9b0ea0 edi: db9b0ea0 ebp: d0e00c20 esp: db861f20 Sep 15 17:35:00 si-server kernel: ds: 0018 es: 0018 ss: 0018 Sep 15 17:35:00 si-server kernel: Process crond (pid: 2653, stackpage=db861000) Sep 15 17:35:00 si-server kernel: Stack: dbd46fc0 dbb9a1c0 c0145fcc db9b0ea0 dbd46fc0 00000007 00000006 fffffff4 Sep 15 17:35:00 si-server kernel: 00000011 00010000 c01219d5 00000011 db860558 00000000 db861f70 db861fa4 Sep 15 17:35:00 si-server kernel: 3339335b 005d3439 db861f90 db861f70 080499c0 14000000 40047ef8 00010000 kernel 0xcc (0xdb861f28)) 0xc5 (0xdb861f48)) (0xdb861fa0)) Sep 16 09:24:44 si-server syslogd 1.4.1: restart.

That is the last thing that happens, up until the reboot, everything before that is just DHCP REQ and ACK stuff for the whole day, pretty much.

Any help would be greatly appreciated. I've googled for this, and I've found a couple of "bugs", but they both seem to refer to earlier kernel versions. This machine *was* running steadily for a couple of years. No software changes were made.

TIA, DSt.