Android : Stucked when switching from another application

Hi. When I switch from my game to another application (like by launching a web link, or by getting back to the android desktop), and try to return in the game, it remains in a black screen, and only the music works. It appears to be blocked, and android tell me that the application doesn't respond. Is there something I missed to make that switch functionality work ?

The weirdest thing is that when I've just installed the game and launch it from the APK Installer, it works perfectly. But anytime I launch it from the desktop, same problem appends.

Anyway, what does I have to do to make this game "switchable" ?