I'm always getting this error when I try to make a movie.

Windows Movie Maker cannot save the movie to the
specified location. Verify the original sourced files used
in the movie are still avalaible, that the location is
still avalaible, and there is enough disk space avalaible
etc...

I don't understand, I have enough place, the source
destination is ok and the original sourced files is ok

XCan anyone help me