Firefox cannot load movies correctly- Due to Mplayer?

[houstonhilton74]

I have Mozilla Firefox version 3.0.3 ,and I have Ubuntu 8.04.1 Hardy Haron LTS. I usually expect that when I go to live video streams on the internet, the video is always laoded correctly, with no errors. When I play videos, such as quicktime (.mov) files, or Windows media player files (.wmv), the Mplayer movie player plugin is a hit-and-miss with loading the video images. It loads, says it is buffering the stream, than displays, "Playing http://****." and only plays the audio of movie,and does not show the picture at all. If I'm lucky, sometimes the video images appear. I can only solve this by manually copying the url and playing it the Totem Standalone movie player, version 2.22.1. I have an Acer Extensa, model 4620Z.