Movie Maker will not let me add additional background music to pictures.

I am currently making a movie, Movie Maker has preformed well until now after I have added several videos, photos, music & edited many times, I tried to add another piece of background music to go alongside a picture. In this particular movie I have already done this many times and it has worked, now when I click the "Add Music" and then click the piece of music I want to add, a tab pops up saying "Music starts after last item: Music starts after the last video or photo in the project" I then continued to click how to fix this problem even though my 30-second music was added in the point of the movie with still 5minutes of no-music pictures. I tried all of the solution even though most of them didn't apply to my problem as I still have so much space to add music. I'm not sure why this is happening & have tried myself several ways of getting any piece of music to be added at any point of the project and the same tab pops up. If anyway could tell me why this is happening or even better a solution to the problem it would be greatly appreciated.