Can't install iceweasel-4.0 on squeeze

[Nicolas GUIOT]

Hi,

I followed the following page : 

http://mozilla.debian.net/ to install on Debian squeeze amd64, iceweasel version 4.0.

So I added this line in sources.list : 
#Firefox 4
deb http://mozilla.debian.net/ squeeze-backports iceweasel-4.0


When running apt-get update, I have the following error : 

W: Failed to fetch http://mozilla.debian.net/dists/squeeze-backports/Release  Unable to find expected entry  iceweasel-4.0/binary-amd64/Packages in Meta-index file (malformed Release file?)

sorry if this has already been asked, I didn't find anything on the internet to help me...

Bye
Nicolas