firefox 3.6.15 ubuntu

[Joep L. Blom]

I have a annoying problem in firefox 3.6.15 in Lucid Lynx where the 
default application cannot be changed. Formerly there was a button 
"Edit" in Edit-> Preferences->Applications where the default application 
could be changed.
Now it uses for some unknown reason 'Virus Scanner' as the default 
application which is completely useless where I would like to see gedit.
Moreover, formerly, when you pressed the button other in the opening 
dialog where you can choose the default application, when you chose 
"other" it gave the list of other applications. Now it opens the users 
home directory (which of course is useless for choosing an application).
I hope somebody can clarify this as it is a great annoyance.
Joep