video playback interrupted

I have a video I'm trying to watch, but QT will only play it in clips. Sometimes the video will have a hiccup towards the end, and you have to move the playbar forward for it to "loop" to the next scene, or otherwise just guess when to "rewind" to the next scene. You have to keep starting the video from almost the beginning, and sometimes it begins at the first scene, with no way to skip to later scenes.

Any help would be appreciated-- thanks!