Issues with music is playing after the last video or photo

I have followed the instructions in the link provided to rectify this, my sequence of photos is one second longer than my music track but I am still getting the same notification, I am not even sure what it means because if there is no photo or video after this one I don't see how it could be playing at all so it's basically not playing, I don't understand why following the instructions hasn't fixed it and I don't know what to do, someone help?