Alice Tutorial problem

I'm using Alice in 8th grade and have them using the 4 tutorials from the opening screen. Several of my students are getting stuck on the "defending naptime" tutorial. It will say they made a mistake and need to go back....and it won't let them move ahead. It seems to be happening at the part where they make the phone ring. Just wondering if anyone has run into this problem. Out of 26 computers it happens to about 7.