It's not a hack problem, it's a timing problem. Or disc speed - I/O problem, however you want to term it.
UBB is trying to write to now.cgi before some other process is done using it and so the file is locked.
I'm not even sure something UNIXy will fix it although UNIX based O/S generally are a bit snappier about disc access and I/O. Perhaps a faster hard drive?
Is there anything else running on the server that does a bit of disc I/O that could be slowing things down? Is your page file too small? That will do it. Not enough RAM will cause swapping and I/O problems too.
