Ubuntuone control panel shows IPCError

[Jacek Nykis]

When I start Ubuntuone control panel it I get a pop up saying "Sorry, an error has occurred and Ubuntu One needs to close.".
"Show details reveals this error message:
"IPCError"

The client will not sync any data or show my data in the cloud.

Here is what I can see when started from a terminal:
$ ubuntuone-control-panel-qt
Unhandled error in Deferred:
Unhandled Error
Traceback (most recent call last):
Failure: ubuntuone.platform.tools.linux.IPCError: org.freedesktop.DBus.Error.Spawn.ChildExited:
Unhandled error in Deferred:
Unhandled Error
Traceback (most recent call last):
Failure: ubuntuone.platform.tools.linux.IPCError: org.freedesktop.DBus.Error.Spawn.ChildExited:
Unhandled error in Deferred:
Unhandled Error
Traceback (most recent call last):
Failure: ubuntuone.platform.tools.linux.IPCError: org.freedesktop.DBus.Error.Spawn.ChildExited:
Unhandled error in Deferred:
Unhandled Error
Traceback (most recent call last):
Failure: ubuntuone.platform.tools.linux.IPCError: org.freedesktop.DBus.Error.Spawn.ChildExited:
INFO:ubuntuone.controlpanel.qt.folders:The warning dialog was shown and also closed (message was 'IPCError').

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: ubuntuone-control-panel-qt 4.1.91-0ubuntu1
ProcVersionSignature: Ubuntu 3.8.0-14.24-generic 3.8.4
Uname: Linux 3.8.0-14-generic x86_64
ApportVersion: 2.9.2-0ubuntu2
Architecture: amd64
Date: Mon Mar 25 09:50:32 2013
InstallationDate: Installed on 2013-01-19 (64 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
MarkForUpload: True
PackageArchitecture: all
SourcePackage: ubuntuone-control-panel
UpgradeStatus: Upgraded to raring on 2013-03-19 (5 days ago)

[Jacek Nykis (jacekn)]

This is no longer happening on the latest raring