gnome-open nautilus is broken

Binary package hint: nautilus

(my ubuntu is localised to French, so every error message is translated)

For apparently no reason, gnome-open suddenly forgot the existence of nautilus :

- In gnome panel, clicking on "places/home" raises the error box
« No application is registered for this kind of file »

- In a terminal : « gnome-open . » raises « Error displaying URL : no application is registered ... »

I have absolutely no clue how this happen (the nastiest thing I was doing is editing the pidgin launcher in the panel menu, if it can help)

A consequence of that (I think) is nautilus doesn't display the desktop until I manually launch it.

Bonus : I don't know if all this is linked, but at exactly the same reboot, gnome-do started to act oddly (not loading the theme I set) and I needed to remove ~/.purple to get pidgin lauching again.

I hope someone can help, and it can help identify what caused all this. (otherwise I'm considering reinstalling very quickly)
Thanks
Marc

ProblemType: Bug
Architecture: i386
DistroRelease: Ubuntu 9.04
ExecutablePath: /usr/bin/nautilus
Package: nautilus 1:2.26.2-0ubuntu2
ProcEnviron:
 PATH=(custom, user)
 LANG=fr_FR.UTF-8
 SHELL=/bin/bash
SourcePackage: nautilus
Uname: Linux 2.6.28-15-generic i686