Thank you for pointing out this problem! 
It is fixed in 3.315, expected to release today. We added extra checking for the presence or absence of the .rtf file to cover all bases.
What is reported here, that MTU and our honored Beta Testers failed to test because we an .rtf file was present, is that deleting the SongBook.rtf fails when it doesn't exist.
We assumed (incorrectly) that Microsoft Windows would return a successful result when deleting a file that is not there. We trusted Microsoft's judgement... which sometimes is not as it should be.