I didn't realize anyone was using this plugin - I made it a long time ago (2013), and haven't looked at it after we upgraded to Qt 5.
It seems all you need to do is get rid of QVariant, so you can try the new version attached.
Note, however, that this plugin is UNSUPPORTED. If it works, great, if not, well...
Edit: Removed version 1.1 which had a bug - use 1.2 below