Since I've started using gnome-mount (as part of Gnome 2.14) I can't mount floppy disks from Nautilus (I can mount them from the console). Searching for the problem it seems to be a known problem of gnome-mount. The problem is fixed in the cvs version of gnome-mount here http://cvs.gnome.org/viewcvs/gnome-mount/src/gnome-mount.c?r1=1.16&r2=1.17. Appling this patch solves the problem. I'm running gnome-mount 0.4-r1.
Created attachment 86893 [details, diff] Patch from gnome website to fix the problem
Fixed in gnome-mount-0.4-r2