Producers or applicants who illegally copy or submit programming material for cablecast may be liable for infringements of copyright including severe civil penalties and/or imprisonment.

Please browse through:
Stanford University Libraries' Copyright & Fair Use
US Government Copyright Office
Digital Millennium Copyright Act summary

While you may not be profiting from using someone's material that's protected by copyright, even if you are a non-profit organization, you may be held liable if it falls out of the bounds of "Fair Use". Find out how to be sure you're protected and about the parameters regarding "Fair Use" by visiting any of the above links.