I periodically get warnings from Kaspersky AV on various sites - for the most part it blocks the problem and loads the rest of the page.
I'm not convinced that there is a harmful file being uploaded, more likely its a badly coded flash advert that fits a pattern.

I have seen other legit websites who have had their software downloads blacklisted by Norton and others, based on one or 2 reports from disgruntled users, or plain malicious ****'s causing trouble.... - another possibility here...?