If you try to use cifs to mount an smb share using the "users" option (making it
possible for any user to mount/umount) cifs gets confused and shows this error
'username specified with no parameter'
fixed in more current mount.cifs and also in 2.6.10 or later kernels (may be
even in earlier kernels). See project page for patches for some earlier
kernels and mount.cifs.c is in SAMBA_3_0 tree