Incorrectly blocked website
I was installing an extention called Download Flash and Video in Firefox from their website (https://addons.mozilla.org/en-US/firefox/addon/download-flash-and-video/?src=ss) when I received a harmful website message for the author's site. I checked in my recent events and found that this site is blocked. I am unable to unblock it. Why is this site tagged as a harmful site and how do I remove the blockage? The iste's url is: fvdmedia.com/fvd-welcome-ff/.
EDIT: Potentially malicious website link