Hi All,
Thanks for the advice. AVG now works...
However, I seem to get this error every few days for some reason

so I wrote a quick app that does the above for you!!
Its been very useful for me so I thought I'd share
Note this has only been tested with AVG-Free version 8 on windows XP. The App
Heres the app (zipped):
http://djfreshbru.com/apps/AVGCTFFix.zip
And heres the source code (for all those paranoid ppl):
http://djfreshbru.com/apps/AVG CTF Fix Source.zip
What does the app do?
1. Deletes
avginfoavi.ctf in
\All Users\Application Data\avg8\update\download\
2. Deletes
avginfowin.ctf in
\All Users\Application Data\avg8\update\download\
3. Runs the AVG Update Application: "C:\PROGRA~1\AVG\AVG8\avgupd.exe /pri=4 /session=0 /aspam=0"
Notes
This *should* remove the invalid CTF files then run the AVG update app. When you run the app, make sure you can see the desktop (minimise all windows) as the AVG Update window doesn't appear on the taskbar and sometimes hides under other windows...
If you have not received the 'Invalid CTF...' warning, DO NOT RUN THIS APP. You may receive additional errors as valid CTF files will be removed.
Any ideas/updates/bugs, please message me.
Thats all folks!