Log Files:
Enter console (via Putty / ssh as is easier to copy out the logs):
dmesg | more
or maybe dmesg | grep error
cat /var/log/messages | grep -v dhcpd | grep -v sshd | grep -v fcron
If there is nothing strange, it could be a kernel panic, that leaves little trace.
Check the machine for hardware problems: Bad memory, high temp, etc...
Try to get a screen of the error. Connect a monitor to the EFW and wait for the error to come, then take a photo of the error.
You can use a webcam saving each n seconds to catch up the error (I did it this way!)
/var/log/message:
Sep 1 00:05:09 endian kernel: [ 2627.075975] fetchipac[11990]: segfault at 1 ip b762ce16 sp bfb57fa8 error 4 in libc-2.3.4.so[b75d9000+114000]
Sep 1 00:10:09 endian kernel: [ 2927.075741] fetchipac[12532]: segfault at 1 ip b7625e16 sp bffbb268 error 4 in libc-2.3.4.so[b75d2000+114000]
Sep 1 00:15:09 endian kernel: [ 3227.078301] fetchipac[13075]: segfault at 1 ip b764be16 sp bfabf3b8 error 4 in libc-2.3.4.so[b75f8000+114000]
Sep 1 00:20:09 endian kernel: [ 3527.082425] fetchipac[13617]: segfault at 1 ip b7659e16 sp bffc2f58 error 4 in libc-2.3.4.so[b7606000+114000]
In the file i got a lot of this errors, can be the cause?
One thing i repair, it is the most restarts happen on the work hours, but off the work hours it restarts too but not with me same often.
Sorry about my english,
Daniel gomes