Could you save the scribe you are working on to the online cloud folder and also let us know the name of the music file you would like added. I will download it and take a look and see if I get the same issue.
With regards the In-App purchase you can restore these. If go through the process of publishing a video the last page before you confirm your purchase has a 'Restore Purchases' button and this syncs back to your iTunes account and if you have already paid for it updates the app to show this. You will normally need to do this if you re-install the app or install it on a new device for the first time.
Well glad it's working for you.
That error is just showing that your account has a marker on it to say it's paid and the restore button does the magic needed to pull that payment back into the product and let you publish videos.