nautilus-script-audio-convert doesn't do anything

I have installed and taken the proper steps to activate the audio-convert script but it doesn't appear in the Nautilus contextual menu.

Steps to reproduce:
Install the script package;
run nautilus-script-manager and activate the script;
restart Nautilus (nautilus -q);
right click on an audio file in nautilus;
no audio convert option appears in the contextual menu.

What should happen:
you should be able to convert files from the contextual menu.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: nautilus-script-audio-convert 0.3.1.1-0ubuntu6
ProcVersionSignature: Ubuntu 3.11.0-11.4-lowlatency 3.11.3
Uname: Linux 3.11.0-11-lowlatency x86_64
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
Date: Wed Oct 30 22:55:23 2013
EcryptfsInUse: Yes
InstallationDate: Installed on 2013-08-22 (69 days ago)
InstallationMedia: Ubuntu-Studio 13.04 "Raring Ringtail" - Release amd64 (20130424)
MarkForUpload: True
PackageArchitecture: all
SourcePackage: audio-convert
UpgradeStatus: Upgraded to saucy on 2013-10-20 (10 days ago)