Before making it too difficult ... I now see in your error-4 picture that you stuffed "(WAV)" in the name; is that correct ? if so, that for sure creates problems, probably this one.
If you had created Galleries I think you would know. But if so, they are just normal folders on the drive you created the Galleries. For that matter, your error-4 picture may show a Gallery root of FLAC (but I can't see whether it's a Gallery or a real music folder), and that FLAC folder would just reside on disk.
Let me know about the (WAV) thing ...
Peter
The (WAV) is either in the artist folder (in which are the albums) or after each album. It's there to remind me to convert them to flac and then edit the tags.
If i do the conversion first, this problem will disappear? Because i have to do it sooner or later