Removing Two black frames...HELP!

hey all,

Here’s my dilemma. When burning a dvd with InterVideo WinDVD creater, i get those two thick black lines above and below the movie so that the movie is squashed and very long. It doesn’t happen when you watch the movie on computer or preview it, just when it’s being burnt and then the final product on dvd.
What the heck is going on and can i remove it? It doesn’t happen to all dvds i burn, only some. HELP ME!!!