"Do you think the music teacher deserves to be fired for this mistake?"
Even you are calling it a mistake...is it really worth trying to destroy someone's career? (Unless, of course, she is bad at teaching music...but that's a different issue.)
When my daughter participated in All State, she had to do all the leg work herself, too. And looked up all the info online, too.
While it's unfortunate that she wasn't more informative and helpful, it does seem to me that you should have checked out the days/dates involved if you knew that participating on a Friday would be an issue. To totally blame your teacher seems a little unfair.
That being said, I *am* sorry about your disappointment.
Sueleen Gay: "Here you go, Bitch, now go make some fukcing lemonade." 10/28/10