Right, 'twas my fault. I've just pushed updated versions of mBarcode and the pythonqtwrapper plugin to Extras-devel. These should provide more debugging output now. In addition the problem was that I'd not added a dep on libshiboken1.0 for the pythonqtplugin (though I have now).

I've also attached a fixed version of the Python code (you need to install python-pyside manually - normally this would be a dep of this python code's deb file. This is quite a large install, but it goes to /opt, so shouldn't be a problem. OTOH as it doesn't actually use PySide you could well be able to remove that import & superclass references (to QtGui.QWidget iirc) and see if it works anyway.)

In any case let me know how you get on, and a Happy New Year to everyone