AVG 8 - Invalid update control CTF file

For a few days now AVG Anti-Virus Free 8 has been complaining about it's database being out of date. When I've tried manually running the update feature I get the following error:

"Invalid Update Control CTF File"

I finally got round to doing something about this yesterday, I did a quick scan for all .CTF files and found a couple in:

C:\Documents and Settings\All Users\Application Data\avg8\update\download

I deleted the .CTF files in this folder (I left the .BIN files alone) and tried running the update feature again. Ran without a problem this time and downloaded an definitions update fine.

I've got no idea how AVG got itself into this state but it was simple to fix. I'm running Windows XP by the way, the location of the files may be different on Windows Vista.