Is it possible to run flash applet with microphone support on Android? I have an applet with microphone support which works fine in all desktop browser. But on Android it says "can't obtain microphone".

Is this obstacle principal or can be overcame?
No, you cannot use a microphone on the mobile version of Flash Player.
From the Action Script Reference Documents:

Runtime microphone support
The Microphone class is not supported in Flash Player running in a mobile browser.