Playback is not working

[rlaffront]

Hello there ! How are you today ?

I am having an annoying problem in Sibelius. For some reason, my playback is not playing the notes.
I am re-doing a music from the paper to Sibelius. Put all the notes and yesterday was working fine. Today when I was putting the rest of the slurs and voice the playback stop working without any reason. And the strange thing is that half of the music the playback works fine and if I keep input the notes in the music I can hear the sound of them without any problem.
I am using Win 7 64bits and I will send the music that I am putting in Sibelius.

Any ideias?

Thanks and Regards