Did you check in quarantine area as to what the detection was? Is it the same detection. In real time scanning there is an option to not scan email attachments but I have it on and hotmail and thunderbird attachments are opened and saved fine.
As well as checking what I suggested also call support though I assume they will try to sell you virus removal.
Hmm as another thought scan with several of the suggested scanners here
Moved to SecurityCenter.