can't open encrypted source folder in nautilus

t says permission denied. When I try with sudo, it says permission denied.

Before mounting, I tried:
- chmodding the source and destination folders deltrem:fuse
- chown root:fuse /dev/fuse
- chown deltrem:fuse /dev/fuse
- chgrp fuse /dev/fuse

In Nautilus, the folder is a file icon.
In Shell, ls -l shows question marks.

What should I do to have a working source folder?

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: encfs 1.7.4-2.4
ProcVersionSignature: Ubuntu 3.2.0-23.36-generic-pae 3.2.14
Uname: Linux 3.2.0-23-generic-pae i686
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu3
Architecture: i386
Date: Tue Apr 17 16:19:09 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta i386 (20120328)
ProcEnviron:
 LANGUAGE=pt_BR:pt:en
 PATH=(custom, no user)
 LANG=pt_BR.UTF-8
 SHELL=/bin/bash
SourcePackage: encfs
UpgradeStatus: No upgrade log present (probably fresh install)