After some hard work, I found that just installing,
The X86_64 bit version of:
mplayer-fonts-1.1-4.lvn6
mplayer-gui-1.0-0.80.20070715svn.lvn7
mplayer-1.0-0.80.20070715svn.lvn7
mplayer-codecs-20061022-1
mplayer-doc-1.0-0.80.20070715svn.lvn7
Then I installed the i386 version mplayerplug-in as such;
rpm -ivh
http://livna-dl.reloumirrors.net/fed....lvn7.i386.rpm
And it worked using the 32 bit Firefox.
Before you use my example of installing mplayerplug-in, go to the website
and check for correct version of mplayerplug-in