compser and audio/physics error

Hi

I’m a casual programmer and have no much experience, but from what I see on my project it seems that

composer has some problems with switching screens that contain physics or audio ( or at least look like it). 

Corona Simulator shows me " Warning: audio error: Requested channel (9) is in use.  

I never used channel 9 , And physics are not working anymore after this error. My “hero” should drop down and it is just floating in fixed position" . It is very similar to problem described in this thread:

http://forums.coronalabs.com/topic/47549-physical-became-very-very-slow-when-update-to-coronasdk-20142295/page-1