Kernal Panics

My G5 Dual is generally very stable, but almost every night, when I put it in to sleep mode, by the next morning the kernal panic screen is up on a grey background, sometimes with the fans whirring away, and I have to re-start.
I regularly run Cocktail, and Tech Tools, but to no avail.

Any ideas?

Cheers!

repair permissions, and then put in your start up cd and repair disk.

Do you have any "non-Apple" RAM in it?

Do you use any 3rd Party USB or print drivers?

Repairing permissions is a good start, but you should try running the "hardware test" CD that came with you computer. Hold C while the computer is booting.