Great app - sound stopped working, no longer iOS5 compatible? – Fish School HD - by Duck Duck Moose Review

My son (special needs) loves this app but for some strange reason the sound has stopped functioning (and not on any other app) so we wonder if it is not compatible with iOS 5 ? Very strange, otherwise I'd give it 5 stars.
Review by jdcarcollector on Fish School HD - by Duck Duck Moose.