Go back, and see my reply. I never was urged to download what you say, but, there is, as I pointed out an add-on which is no more than a link to Dr.Web online antivirus link.
The way you stated your concern did not tell the entire story. As far as I am concerned, if you have a good antivirus software, you do not need an online scanner.
UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.1) Gecko/20090715 Firefox/3.5.1
"I've got a very poor sense of direction. I keep forgetting which way is forwards."
WinXP, SP3, 512 MB, 3.0.15 regular, 3.5.5 regular and portable , TB2.0.0.23, Flock2.5.2, IE8.0, SM2.0, Google Chrome2.0.x, Zone Alarm Firewall; AVG9.0, JRE1.6_17