These online Video site's host links to content that is hosted elsewhere, if that link is not working, then it may have been removed for copyright infringement by the other site hosting the video.
Not every video link on free video site's will work and you will find a lot of them are nothing more than a collection of hyper-links to other sites.
Project Free TV has been down for a while but the good news is their are plenty of other ones available that still do work. http://www.ovguide.com
or alluc.org are good places to try for alternatives.
Some people have being saying they got shut down due to piracy, that is the wrong answer... How can you shut down a website that hosts links to sites not even in their own country. People should try to get the facts straight!
If a DVD I own is scratched beyond repair and I download a backed-up copy of the episode or movie is that piracy? No... Piracy is the little guy standing on the street corner going "you want DVD?" It's not piracy if its free but it is piracy when you re-sell it!