I tried uploading my score "Grave Goods" via the "Publish "option, and got a message to say that it could not be uploaded, and a link to this forum. So here I am!
I would also like to report that attempting to upload from the My Scores score itself didn't update the mp3, so when I played it I soon realised that what I was seeing didn't match what I was hearing..
The only viable option seems to be to delete the published score and then specify that it is a new score.
I am really upset at all these problems associated with MS4, both publishing and playback, and am considering trying another solution.