Does anyone else have this problem?

When I'm watching a video, (it doesn't really matter what source) it will only load up to a certain point. It varies on the video, but it will stop playing/loading. If I slide the time marker past the stop, it will start loading from that point, so I just move it back to before where I stopped the first time.

This happens all to often, and yes, I've got the latest flash player.

Firefox v 2.0.0.14