Bit of caution here, firstly if this company is the same Wondershare that I've seen spamming numerous forums for the last 5 years the quality of this product is going to be questionable.
Whenever downloading an unknown program first research it thoroughly, be sure to right click it and scan it for virus before installing and lastly download from the source. If you're going to download something like Virtualdub for example which is great little program for video processing you'd want to go right to Virtualdub's site
. What happens a lot of times especially with open source and free programs is someone will recompile it with a virus and offer it for download.
The video gimmick to get you to download something has been used often in the past because people have become accustomed to legitimate warnings about a codec not being available or other warnings about the Flash Plugin not being up to date.. FLV is a legitimate format however it's used through the Flash plugin from Adobe. Anything regarding this should be coming from Adobe. Any prompt to install anything from any site needs to be scrutinized. Truthfully other than the plugins from Adobe I can think of two that most people will want and that is Silverlight from Microsoft which I use on this site and JAVA.