Windows Movie Maker: "Unknow error"

Can someone help me; PLEASE?
Whenever I try to import anything (video, image, sound, or even record it from my webcam); an error pops up, saying:
I know that it is an unknow error because I used to have the Portuguese version, and it said: "Erro desconhecido", wich means unknown error.

It used to import everything correctly, but know...

Can someone here in the community help me?
Oh, and if the help is: "Google it." than, thank you veeeeeeery much... I would never have tought of it. Wow, you are my Lord. Oh thank you Lord. -_-

If you need a video to describe the problem a little better...:
http://www.sendspace.com/file/wsusp1

PLEASE, help me.

Lawl Windows Movie Maker.
The solution is get something better.

Well, what do you suggest?
(Freeware program, please)
(Don't "Google it." me...)

Quality isn't cheap. I suggest Adobe Premere, or Studio 10.

Well, I didn't exactly want quality... But I'll try those.
Thanks Segmint.