AVG scanning not working as expected with Thunderbird

I am using Mozilla Thunderbird for mail send/receive. My system is having Windows 7 Professional, AMD processor with AVG Antivirus Free edition installed.
I wanted to use AVG along with Thunderbird. But looks like it is not working as expected. With Yahoo it is scanning the mails I am sending and receiving Both. When using Hotmail only incoming Hotmail is being scanned. While sending mail from Hotmail it is showing error trying to connect to 127.0.0.1 When I want to use Gmail I can't send/receive mails with same server error.
I have followed all given instructions for AVG installation, but I am not sure what is the problem here.
