Problem with playing the movie

[ViolaHeart]

I have the latest version of VLC player and I tried to watch one flv movie but after the movie had play 1 hour it suddenly stops playing and screen turns to black. if i click "Play" it starts to show movie from the beginning. this happens always in same point.
Sorry if there are some misspellings, I am from Finland
but I hope someone could help me with this problem. thank you.