Yes… BUT in some cases the offline installer doesn’t work, whereas the online one does. It has something to do with the wrong SFX in some installers.

Offline ones…

http://files.avast.com/iavs9x/avast_free_antivirus_setup.exe
http://files.avast.com/iavs9x/avast_pro_antivirus_setup.exe
http://files.avast.com/iavs9x/avast_internet_security_setup.exe
http://files.avast.com/iavs9x/avast_premier_antivirus_setup.exe