Firefox File types disabled

[Albert]

Breezy; Firefox 1.0.7(Ubuntu compiled)
Does any user of Firefox know why 
Edit->Preferences->Downloads->FileTypes has the "Change Action" and 
"Remove" buttons disabled?  And the Plugins dialog showing ALL filetypes 
enabled?  This does not match the help description of these preferences. 
  But most importantly, with all filetypes enabled Firefox tries to 
handle each filetype with some unknown program that always fails.  For 
the video player Totem or VLC to work correctly, all firefox plugin file 
types must be disabled and with the File Type buttons disabled, there is 
no way to specify which video player to use for which file type. 
Firefox uses both on different occasions, but without me specifying 
which to use for which type.