1. i do not know what is wrong.
2. create a text file extension *.reg
REGEDIT4
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MediaPlayer\ShimInclusionList]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MediaPlayer\ShimInclusionList\mozilla.exe]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MediaPlayer\ShimInclusionList\K-Meleon.exe]
http://gemal.dk/blog/2003/08/07/use_windows_media_player_9_in_mozilla/
This is a Windows bug - repeat bottom line for exery Mozilla version e.g. FFox...
I use Mozilla.exe and k-meleon.exe how could You tell:-) - greetings