I was having problems in accessing most of my webinar by requiring my firefox(ver.2.0.5)
a plugin. So i came out a better solution specially to those newbies like me.

My configuration was a extracted Firefox and Real 10, all in .tar.gz balls.

Real Player 10
- extract from source(i.e. /usr/src/real)
- configure using ./configure
- then make command
- then make install command

After all commands you've executed the commands, now you must copy the extracted files to your firefox directory.

I extracted my firefox and Real Player 10 to: /usr/src/firefox and /usr/src/real
copy the plugin
from /usr/src/real/mozilla -->nphelix.so
to /usr/src/firefox/plugins

then copy
from /usr/src/real/mozilla ---> nphelix.xpt
to /usr/src/firefox/components

Lastly, open the firefox web browser,
on the address bar, type-> about:config to open the configuration settings.

Add new boolean, network.protocol-handler.external.rtsp, set the value = true

Add new string, network.protocol-handler.app.rtsp, set the value = /usr/src/real

now you can play real files on you Firefox
Cheers!

That seems rather complicated. I would install the rpm from http://www.real.com/linux and create a symlink from /usr/local/RealPlayer/mozilla/* to the firefox plugins directory or to /usr/lib/mozilla/plugins.