Play Back Problem

Hi

I installed Symphony Pro on my iPad this weekend - when I play back a simple score I find the display gets corrupted - particularly lines from the staves disappear - sometimes the descenders on the notes.

I has upgraded to iOS 5 prior to buying this app so is it a problem with iOS 5? Or there some other fix?

Any help appreciated - generally I think this is a fantastic app - very useful for improving your playing

Thanks

BenR