fprint_demo does not have access to the device

[Lazy]

Topic says it all. Here is the output from console.

~$ fprint_demo
libusb couldn't open USB device /dev/bus/usb/001/004: Permission denied.
libusb requires write access to USB device nodes.

And here you can see how the device directories look like:
~$ ls -l /dev/bus/usb/001/
total 0
crw-rw-r-- 1 root root 189, 0 2011-09-14 13:02 001
crw-rw-r-- 1 root root 189, 1 2011-09-14 13:02 002
crw-rw-r-- 1 root root 189, 3 2011-09-14 13:02 004
crw-rw-r-- 1 root root 189, 4 2011-09-14 13:02 005

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: fprint-demo 20080303git-5ubuntu1
ProcVersionSignature: Ubuntu 3.0.0-11.17-generic 3.0.4
Uname: Linux 3.0.0-11-generic x86_64
ApportVersion: 1.22.1-0ubuntu2
Architecture: amd64
Date: Wed Sep 14 20:14:54 2011
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007)
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: fprint-demo
UpgradeStatus: Upgraded to oneiric on 2011-09-13 (1 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Pavel Zastavnyi (assedoo-l)]

This defect has a workaround.
1. Add to /etc/rc.local file next commamnd: chgrp -R plugdev /dev/bus/usb/

2. Add your user to plugdev group by executing next command: sudo usermod -a -G plugdev $USER

[Indie (alanlitster)]

You don't need to modify /etc/rc.local. The way it's done in the one distributed with Ubuntu is by means of a UDEV rule. All you need to do is append the following

# Device Validity VFS5011
ATTRS{idVendor}=="138a", ATTRS{idProduct}=="0011", MODE="0664", GROUP="plugdev"

to /lib/udev/rules.d/40-libfprint0.rules or create your own (41-libfprint0-custom.rules) so it doesn't get overwritten.