Error Synchronizing Project/cannot preview

[cass16x]

Hi, I am trying to make a dvd of pictures, using Windows DVD Maker, from a family reunion and would love to have music play along with it. The project worked just fine until I added the 3 songs I want to add. Now when I open the project it says 'error synchronizing project' but still lets me open it. When I try to preview the project it says that it 'cannot create DVD preview', or it freezes up and closes. When I try to burn the project it stops at 3.5% and says error burning dvd right before it starts, although it starts burning anyways. It's obviously not working because of the music, which are mp3 format, but without the music the whole DVD kinda stinks. I have been searching everywhere and have found no answers. PLEASE HELP!