I don't believe it is a false positive, on the hxxp://greg866.tripod.com/tert9.wmv that page has an associated favico.ico file, this the web browser tries to load the icon to the left of the browsers address bar and this file has been hacked.
So avast also alerts on the favico.ico file, image 1.
Checking the page source of that alert, there is a script tag after the closing html tag (a standards no, no and most suspect. Add to that and the content of the script tag is obfuscated javascript, making it even more suspect (image 2, the sctirpt is on a single line, which I have broken down to make it easier to view).
Why you can't see the favico.ico file is beyond me, but perhaps it is something that tripod controls, I don't use tripod so I can't say.