This might help you KB.
Follow these instructions to remove and reset the plugins:
- Close Firefox
- Navigate to C:\Program Files\Mozilla Firefox\Plugins\
- Delete all of the npqtplugin.dll files: npqtplugin.dll, npqtplugin2.dll, etc.
- Navigate to C:\Program Files\Quicktime\Plugins\
- Delete all of the npqtplugin.dll files
- Reset your Quicktime mime settings
And if your MIME setting are giving you trouble (I'll assume you haven't already looked at something for those

) then try these settings:
Quicktime 7 and Alternative 1.5
- Close all instances of Firefox
- Go to Start > Control Panel > Quicktime 7
- Go to the Audio Tab
- If using Alternative, select "General Midi" under "Music Synthesizer"
- Go to the Browser tab and click "Mime Settings"
- Enable the file types you wish Quicktime to handle. Do not enable Flash.
- Click OK
- Go to the Streaming tab
- Choose the connection that best matches your current Internet connection speed
- Click OK
Taken from <a href="http://forums.mozillazine.org/viewtopic.php?t=206210">here</a>.