When I was adding a contact today, on Gmail, all of the sudden, Avast! pops up unexpectedly with this:
This surprised me, where did this come from?
How did I get infected with this?
Nobody knows anything… 
Most probably a false positive. I higly doubt GMail would allow such attachements like VBS,PIF,EXE,SCR etc…
You are not infected. Avast! just warns you that the link (what is the full link by the way) contains some viral data. It might be a false positive or it might be a virus in your mail.
What is the exact link? Is it not an email message that contains some attachments? Perhaps the attachments are causing this warning (false positive or not). Can you reproduce the warning or did it happen just once?
I also wonder why don’t you use HTTPS instead of regular HTTP for GMAIL ?
I want to use https… it somehow turns off when I am finished logging in…