I have a movie with the extension .m4v that imports to iTunes library and shows the little preview screen & information. I have tried to synch it to my iPad and get and error like: not copied because could not be copied to this iPad. I have a lot of other videos with this extension and no problem synching, even this morning when I was also trying to do the problem movie. All others went over fine. Have googled and am just not seeing the solution. What could be wrong?