Hi, I think I may have found a solution. It worked for me. I uninstalled Firefox 5.0 and tried unsuccessfully to download Firefox 4.0. So, I reinstalled Firefox 5.0 and the Download this Video Button now appears in my browser's video window. Clicked on Download this Video and it worked like a charm.

Thanks. It works somehow. For me, as an administrator of my lap it wotks, but for my other users, that aren't administrators, still doesn't :(