soundconverter crashed with TypeError in set_string(): GConf.Client.set_string() argument 2 must be string, not None

[justin curtis mathews]

Happens when adding files and having a second window open.

1. Kubuntu 12.04 Beta 2 (development branch)
2. soundconverter:
            Installed: 1.5.4-1
            Candidate: 1.5.4-1
            Version Table:
   *** 1.5.4-1 0
                 500 http://us.archive.ubuntu.com/ubuntu/ precise/universe amd64 Packages
                 100 /var/lib/dpkg/status

3. I close the second window. But setting it to run only one instance would be nice then this may not happen again. (Also would save the processor because mine is overheating.)
4. The second instance closed itself with an error.

ProblemType: Crash
DistroRelease: Ubuntu 12.04
Package: soundconverter 1.5.4-1
ProcVersionSignature: Ubuntu 3.2.0-21.34-generic 3.2.13
Uname: Linux 3.2.0-21-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 2.0-0ubuntu2
Architecture: amd64
Date: Mon Apr 2 19:47:57 2012
ExecutablePath: /usr/bin/soundconverter
InstallationMedia: Kubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
InterpreterPath: /usr/bin/python2.7
PackageArchitecture: all
ProcCmdline: /usr/bin/python -tt /usr/bin/soundconverter
ProcEnviron:
 LANGUAGE=en_US
 LANG=en_US.UTF-8
 SHELL=/bin/bash
PythonArgs: ['/usr/bin/soundconverter']
SourcePackage: soundconverter
Title: soundconverter crashed with TypeError in set_string(): GConf.Client.set_string() argument 2 must be string, not None
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare

[Launchpad Janitor (janitor)]

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