XPSP2 Install Woes

[UMCPWintermute]

I'm attempting to install the Network Install of XPSP2 (downloaded directly from MSFT's website, so no chance of fake installs) onto an XPSP1 system (completely up to date with hotfixes/patches, Office XPSP3, McAfee VirusScan 8i (RC)).

It gets as far as finishing backing up files and attempts to create a system restore point (even though I've disabled system restore) and proceeds to crap out installing.

"Unable to read from or write to the database"

Anyone else seen this problem? I really don't want to turn System Restore back on, as I'm planning on rolling out the install to about a hundred workstations - all of which have system restore turned off and that's not an acceptable solution.

Thanks

 

[UMCPWintermute]

System Restore was not the issue - I've tried it both on and off. Nor is harddrive space (I was low on the C drive, but I freed up several gigs and still have the issues). I've used the same SP2 executable to successfully install on several other machines, so that's not the issue (and the checksum matches MSFT's posted checksum).

Thoughts?