Does the latest version of Avast home support installation in 64-bit mode on Vista (Beta 2)? I installed it, and in Task Manager all the providers are running with the post-fix *32 which means it’s running in 32-bit mode afaik
Hello and Welcome ;D
Yes, avast! supports Vista x64 (Beta 2) 
For more info see:
http://avast.com/eng/avast-antivirus-and-windows-vista.html
and about x64 support see:
http://avast.com/eng/x64.html 