PowerPoint, Music and Transitions

I have created a slide show with music embedded using PP Version 10. It all works great until I change the music to start later in the song using
custom animation, effect options, start playing from time: 25 seconds (or some other time). Then music works fine, but the slide transitions stop
working and the show does not move off the slide with the music icon. If you press ENTER twice, then the program takes off and works. I can
replicate this and it doesn’t matter whether it’s an MP3 or a CD file. Please help