marini23, unfortunately I don’t know how to help you with this problem.
pterosilbene, I haven’t followed this adventure much as I’ve installed this plugin only on one of my websites without having too many problems with my modified version.
Anyway, I think you can’t start from a newer version and patch it with my modified version, but you should install my modified version from scratch uninstalling any other version.
In my tests, I noticed that if you do this you won’t lose your work because it remains saved in the database. So I suggest you to make a full backup of your website and then uninstall the 0.8.4 version and install the modified 0.7.6 version and see what happens. You could this on in test environment and not on the production version of your website just to avoid any problem.
Try this and then let me know. ??