If I interpret the error message correctly, it complains to not being able to remove a directory without a name. What's going on here?
Most probably the cause is some kind of setting, because the error now appears with any version I tested. If the reason were to be found in the program, it should have appeared after an update, but it didn't.
Indeed I changed the settings for storage recently. Some time ago I changed the storage directory but this did not cause any problem. As far as I remember the problems began when I began experimenting with the "append" checkboxes.
Now checking on or off any of these doesn't change the behavior. Clearing the whole directory doesn't change anything either.
Please see the attached screenshots.