The solution is to apply this patch http://www.linuxfromscratch.org/patc...ocking-1.patch
to cups 1.4.4 and recompile it.
This way, you can keep gnome-vfs and use cups 1.4.4 and printing works again.
This fixes the problem at least here with :
- firefox 4.0b7
- cups 1.4.4
It has still to be confirmed on :
- slackware 13.1
- slackware64 13.1
With both firefox 3.6 and 4.0beta