appgrid.py crashed with gi._glib.GError in draw_icon(): Icon 'unknown' not present in theme

ukhgl

ProblemType: Crash
DistroRelease: Ubuntu 14.04
Package: appgrid 0.199 [origin: LP-PPA-appgrid-stable]
ProcVersionSignature: Ubuntu 3.13.0-39.66-generic 3.13.11.8
Uname: Linux 3.13.0-39-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.6
Architecture: amd64
CrashDB: {"impl": "launchpad", "project": "appgrid"}
CurrentDesktop: KDE
Date: Sun Nov 2 18:52:29 2014
ExecutablePath: /usr/share/appgrid/appgrid.py
InstallationDate: Installed on 2014-10-24 (9 days ago)
InstallationMedia: Kubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
InterpreterPath: /usr/bin/python3.4
PackageArchitecture: all
ProcCmdline: /usr/bin/python3 /usr/share/appgrid/appgrid.py
ProcEnviron:
 LANGUAGE=en_US
 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 gi._glib.GError in draw_icon(): Icon 'unknown' not present in theme
Traceback:
 Traceback (most recent call last):
   File "/usr/share/appgrid/widgets/removal_warnings.py", line 41, in draw_icon
     pb = icontheme.load_icon('unknown', 32, 0)
 gi._glib.GError: Icon 'unknown' not present in theme
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip libvirtd lpadmin plugdev sambashare sudo