RealPlayer
From MozillaZine Knowledge Base
Windows
If you install Firefox after having installed RealPlayer, you will need to copy some files into your plugins folder so that it can be recognised.
You need to copy:
C:\Program Files\Real\RealPlayer\Netscape6\nppl3260.xpt
to
C:\Program Files\Mozilla Firefox\components\nppl3260.xpt
and
C:\Program Files\Real\RealPlayer\Netscape6\nppl3260.dll
to
C:\Program Files\Mozilla Firefox\Plugins\nppl3260.dll
An alternative is to uninstall and reinstall RealPlayer as this will ensure Firefox is recognised and the neccessary files copied.
Vanishing Controls
The Windows Plugin for Firefox had a problem whereby after using a control button it would vanish. If you are still experiencing this you should install the latest version of RealPlayer. You may also then need to follow the manual steps described above to apply the fix.