soundconverter won't launch. locale wrong

[Edward]

$ soundconverter
SoundConverter 1.4.4

(process:8411): Gtk-WARNING **: Locale not supported by C library.
 Using the fallback 'C' locale.
  using Gstreamer version: 0.10.28, Python binding version: 0.10.18
Traceback (most recent call last):
  File "/usr/bin/soundconverter", line 108, in <module>
    locale.setlocale(locale.LC_ALL,"")
  File "/usr/lib/python2.6/locale.py", line 513, in setlocale
    return _setlocale(category, locale)
locale.Error: unsupported locale setting

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: soundconverter 1.4.4-2
ProcVersionSignature: Ubuntu 2.6.32-41.89-generic 2.6.32.59+drm33.24
Uname: Linux 2.6.32-41-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Fri May 18 09:57:07 2012
InstallationMedia: Ubuntu 10.04.3 LTS "Lucid Lynx" - Release amd64 (20110720.1)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=C:en
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: soundconverter