Ok, well first of all, NEVER EVER open an email from an unknown sender. So many viruses are being sent by email because amatuer users are known to open any email. AVG is not the best AV around, so it may not be picking up this virus if there was one. If the email was from an unknown sender, don't even bother scanning it, just don't open it! But if this email was from a known sender, I really can't help you that much. Try searching your error on google, and let's hope that it gives you some answers, and if other forums come up relating to your problem, they can be of help as well.
I am running WinXP Home SP2, Firefox 22.214.171.124, Adblock, ZoneAlarm Pro, and Norton AV 2006. Sometimes when I receive an email with an attachment that I try to open in Windows Media Player, I get the above message. I have no idea if it is a setting within Norton, ZoneAlarm, or what settings I need to change. Any ideas has to how I can open these attachments?
The email states that the mail and attachments have been checked by AVG and no viruses found.