Wikimedia Bugzilla is closed!

If I try to modify or create an article on (fr)Wikipedia, on 1.0.6 Firefox,
either from my Unix tektro server (cdfpcs2.in2p3.fr and cdfweb.in2p3.fr), or
from my Windows portable, I get the question 
"You  have chosen to open index.php which is a : PHP file
from : http://fr.wikipedia.org What should Firefox do with this file ?
¤ Open with  [ Browse... ]
¤ Save to Disk                  [ Cancel ]  [  OK   ]
This occurs '''only''' for (fr)articles, not for (fr)sections, nor for (en)
or (de)articles. I didn't find any solution by browsing. If I save, I get the
following index.php :

[Process] 
Type=Edit text ;  Engine=MediaWiki   ;  Script=http://fr.wikipedia.org/w/index.php 
Server=http://fr.wikipedia.org  ;  Path=/w 
Special namespace=Special 
[File] 
Extension=wiki 
URL=http://fr.wikipedia.org/w/index.php?title=Particule_%C3%A9l%C3%A9mentaire&a\
ction=edit&internaledit=true