It looks like a lot of songs are now inaccessible and may have been removed from dropbox.
You can try and direct messaging the author if you still want access to these songs. But seeing as there hasn’t been any activity from rolling green, there is no guarantee that you can get a response.
You are about to leave Rhythm Gaming World and access the external songs DB. While no song or file sold for commercially available videogames is hosted there and only fan generated content is allowed, Rhythm Gaming World has no direct control over the database and no files are hosted here. Alright, we had to made you aware of this, now you can visit the database!