Windows movie maker

Basicly When I import a video clip and play it normally in the program its fine. But when I drag the files into the storyboard or timeline the visual is gone, all I can hear is audio. Also when this happens a green arrow appears on my prossesses bar next to the clock and when i click it a small window comes up

Its got tabs on it and its called “DirectVobSub (auto-loading version) Properties” and the tab is at Main, then when I look there is an empty box with an open Icon next to it.. All this doesnt make sense to me and all I want to do it some editing... can anyone help me.

On summer vacation. Will be back in september.