GLib-CRITICAL **: g_variant_new_string: assertion `string != NULL' failed

[funicorn]

Since upgrade to Quantal, Ubuntu keeps printing the warning 'GLib-CRITICAL **: g_variant_new_string: assertion `string != NULL' failed' on every opened gtk application. I don't know where it comes from. Someone said it may be related to canberra and/or canberra-pixbuf packages. I'm not sure it's the case.

The warning shows over and over again on each gtk-based window action, like open a new window, click on menus or buttons and so on. Application runs with no problem, just the warning is really driving me crazy. I googled a lot and found little information on this issue. I think maybe if I file it there is someone who knows something about it and can help me out.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: libcanberra0 0.29-0ubuntu2
Uname: Linux 3.6.3-030603-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.6.1-0ubuntu4
Architecture: amd64
CheckboxSubmission: dc89d7045010e30edab47e64ddffb63e
CheckboxSystem: 2954e74ba17fb0e37fc942cd1d9fab4e
Date: Mon Oct 22 22:23:37 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MarkForUpload: True
SourcePackage: libcanberra
UpgradeStatus: Upgraded to quantal on 2012-09-16 (35 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.