I keep getting this "bounce-back" email...The message begins like "Hi. This is the qmail-send program at roc-smtp-sun.choiceone.net. I'm afraid I wasn't able to deliver your message to the following addresses. This is a permanent error; I've given up. Sorry it didn't work out." I noticed that the roc-stmp-sun.coiceone.net changed between two of these messages.
Is this a virus?