Movie Maker "not implemented" error message

Last night I started a movie maker project and spent more than 2 hours
working on it. I than stopped, saved it as a movie maker project and turned
off the laptop. Today, when I opened the file, I had all the files I used
ther but no video on the timeline! Instead it showed a message saying
(translation from portuguese) "not implemented". I have no idea what this is
and I don't understand how this could happen, as the file says it was last
modified at the time I saved it before closing it! I appreciate any help.
Thanks.

I have exactly the same problem... And all over the web their are ppl having
the same problem but no solutions at all... It's a serious, anoying bug in
the program i thought to be great.

So. Working on a movie, save it normally close program, restart program,
trying to reopen project, error message: not implemented