Invalid Update Control CTF file
After 10 to 15 minutes searching my computer for the CTF file, I found it at
C:\Documents and Settings\All Users\Application Data\avg8\update\download.In the folder, I saw two .ctf file, which is avginfoavi.ctf and avginfowin.ctf, I delete both files and try to run update again, and it was successful.
The above folder is valid for Windows XP. For Windows Vista user, try locate .CTF file folder C:\Users\All Users\avg8\update\download.