Carbonite back up blocked

Hello! I think I posted this in the wrong place a few days ago –
I just installed avast! after frustrating experience with ESET and Windows vista issues. Things seem to be working well w/ avast except I don’t think my “Carbonite” backup is able to get through the Firewall in order to backup my files. Can you tell me how to do that? I’m sure there must be a way. tHANKS!