Since yesterday, when trying to attach a zip file to an email using my Yahoo account, I get a message about a "Malformed container violation" virus and the message is not sent. This happens even if I try to attach a zip which I have sent successfully within the last week. If I send the message and zip using my Tiscali account it is sent without difficulty, and if I send it to my own Yahoo address it arrives, is scanned with a "no virus found" result, and downloads perfectly. Neither my AVG anti-virus nor the Norton spyware scanner on my Yahoo toolbar can find anything wrong. Any suggestions, please?