Fant problemet, virker fint nå.
http://free.avg.com/faq.num-1243#faq_1243
1567:
AVG update issue - Invalid update control CTF file
If you receive the "Invalid update control CTF file" message during AVG
update, most probably the update control files are corrupted. In this case
it is necessary to delete these files. During a next attempt to update AVG,
new control files should be downloaded and update process should be
completed without any difficulties. Please kindly follow these steps to
delete mentioned control files:
a.. Download the utility from the link below to your hard drive
deleteupdatefiles.exe
b.. Run the downloaded utility (command line window will appear for a
short time)
c.. Try to update the AVG program