dont know if it makes a difference, but i activated with the Win7 WAIK on 9.0 SP2
Try excluding that folder from AV, maybe it is so big that AV is still scanning it when the installer tries to access it.
You likely have a bad install.
I would recommend downloading it and reinstalling it again.
I have seen this happen when a .ISO image was burned and it was a bad burn, etc.
If it has already been installed, remove it from Add/Remove Programs and delete any directory structure and files that remain in C:\Program Files\Windows AIK\
After that reinstall the WAIK and try again?
I've downloaded the iso image twice and reinstall the WAIK and still no luck .. i still encounter thesame error...