Vlk
4
It basically means that the current version of avast does not work correctly with your setup: AMD64 + XP SP2.
The problem will be solved by the next program update, but in the meantime, a work around is to remove the /NOEXECUTE flag from c:\boot.ini…
This will turn off the new DEP (Data Execution Prevention) feature of SP2 (that only works on 64bit processors) but will effectively enable avast.
Thanks
Vlk