I had the same problem and the deleting of the config file didn't help. Found out that the problem was one "ä"-character in one of my imagefiles in the default folder the application tries to scan in first run (in my case MyDocs/DCIM). Renamed that file and run the MaePygalleryQML again. It took a while (over 10secs), but finally it opened and started showing the thumbnails. Maybe the gallery can't handle non-ascii filenames with characters like ä,ö ot ü.

Edit: still trying to figure why it runs from the console but not from desktop...