Describe your setup a little more. What version of apache, php, and zend are you running. Are you running any other php accelerators.
Do you have any non-standard (by DA) modules compiled into apache.
The nice people in DirectAdmin support helped figure it out.
It ended up being Webalizer (Which I had temp. set a cron for, but forgot about) giving out the error. The error is only happening once a day now not fo much filling up my logs.
But now what's in my logs is even funnier.
[Tue Dec 13 17:28:41 2005] [error] [client 137.224.***.***] File does not exist: /var/www/html/tgp/pv0408051/images/Anetta_Keys_21sextury_Free_TGP_02.jpg
And this one begins to insult linux a bit
[Wed Dec 14 03:29:04 2005] [error] [client 64.252.***.**] File does not exist: /var/www/html/scripts/..%5c%5c../winnt/system32/cmd.exe
Hehehe. I wonder why people are trying to run exe scripts where they don't even exist.