Version 4.1 cannot protect Hotmail. As you’re using the 4.5, can you see in the headers of the messages (Right click the message, choose Properties and Details), for instance:

X-Antivirus: avast! (VPS 0444-1, 27/10/2004), Inbound message
X-Antivirus-Status: Clean

Do you have these lines there or not?
If not, well, you’re in danger :-\