ok i have some answers
Divij Kumar, thanx for the how-to, but i never got to packaging your swf since compiling my own project with "Deployment - Apple App Store" instead of "Quick publishing for device debugging" did the trick.
The app then worked fine.
the quick publishing was the problem, at least in my case
THANX ALL
btw, the recording starts a bit late on my iPhone 3Gs - but this is the iOS's fault - i checked and the built-in app "Voice Memos" is also late. I need in my app instant recording so I have a constant buffer recording and i use the buttons to mark in and out points instead of adding and removing SampleEvents listeners like we all did here.
cheers