appgrid.py crashed with TypeError in /usr/share/appgrid/appdata/helpers.py: unsupported operand type(s) for +: 'NoneType' and 'str'

Ubuntu app grid crashes when installed on linux mint bubba version.

ProblemType: Crash
DistroRelease: Ubuntu 14.04
Package: appgrid 0.213 [origin: LP-PPA-appgrid-stable]
ProcVersionSignature: Ubuntu 3.13.0-46.79-generic 3.13.11-ckt15
Uname: Linux 3.13.0-46-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.1-0ubuntu3.7
Architecture: amd64
CrashCounter: 1
CrashDB: {"impl": "launchpad", "project": "appgrid"}
CurrentDesktop: X-Cinnamon
Date: Wed Mar 18 01:56:00 2015
ExecutablePath: /usr/share/appgrid/appgrid.py
InstallationDate: Installed on 2015-03-18 (0 days ago)
InstallationMedia: Custom 14.04 - Release amd64
InterpreterPath: /usr/bin/python3.4
PackageArchitecture: all
ProcCmdline: /usr/bin/python3 /usr/share/appgrid/appgrid.py
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
PythonArgs: ['/usr/share/appgrid/appgrid.py']
SourcePackage: appgrid
Title: appgrid.py crashed with TypeError in /usr/share/appgrid/appdata/helpers.py: unsupported operand type(s) for +: 'NoneType' and 'str'
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo