This happened to me as well. My channel got a strike because I uploaded HOUSE ON HAUNTED HILL which is a public domain film. Here's the discussion I made here:

http://productforums.google.com/forum/#!searchin/youtube/house$20on$20haunted$20hill/youtube/iVY3BsYZLds/3eABW3EAXJoJ

The idea that Youtube can put a strike on your account for uploading a PD film is insane and tells me that YOUTUBE is not YOUTUDE anymore but THEYTUBE.