Mozilla/thunderbird/firefox vid file problem

[Chuck Campbell]

I've got FC-1 and rh-9 boxes which are running their stock mozilla.  I
installed thunderbird (via rpm from a web search) on the rh-9 box, and I 
built firefox (via srpm from a web search) on the FC-1 box.

Now, I'm trying to convince my wife that this is a valid replacement for her
windopws box, but I can't get any of the above to play any of the .mpg 
clips from a web page.

Does this require some sort of plugin that I don't know about?

I added the full path name and xmms as a helper app, but all that does is
pop up a dialogue box asking me to select the file to play.  I just want it
to play the file I'm pointing at on the web.

(My daughter wants to see herself skiing, NOW  --  five year olds have such
patience :-)

thanks,
-chuck