What about www.gainward.com, the second I click on one of the Products listing (enthusiast, performance, value, desktop range) the exact same window popus up
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There are some script tags on that page that don't have the inner javascript quoted out and that is probably what is causing the alert although the actual script doesn't look malicious.
Hopefully it will be dealt with as quickly.
Have you reported the FP ?
Send an email with the URL to
virus@avast.com with information, VPS version, Malware name, much as you have done in your post in email body, a link to this topic might help and false positive in the email subject.