При установке FUSE нет файла /proc/fs/fuse/dev, хотя о нём пишется во всех доках, включая http://fuse.sourceforge.net/ --
The FUSE kernel module and the FUSE library communicate via a special file descriptor which is obtained by opening /proc/fs/fuse/dev. This file can be opened multiple times, and the obtained file descriptor is passed to the mount syscall, to match up the descriptor with the mounted filesystem.
Ядро 2.6.11, fuse 2.4.0-pre2. На ядрах 2.4.* всё нормально создавалось и работало.