A bug cropped up in iOS 7 that appears to affect any AIR app that uses sound. The bug pops up a dialog box requesting microphone permission the first time your app is run under iOS 7 (even if your app does not use the microphone). After a user clicks “Don’t Allow” or “OK” it will not re-appear- but this unexpected dialog box can be off-putting to anyone using your app under iOS 7.
I submitted a bug for this and Adobe fixed the issue in SDK 3.9 (beta): https://bugbase.adobe.com/index.cfm?event=bug&id=3609631
Recompiling your app against AIR SDK 3.9 should address this issue. You can find the latest AIR SDK here: http://labs.adobe.com/downloads/air.html