You are running the "full" version (or Pro as I think they call it)? I do recall that the demo myKeypad did tend to close on its own. I am running both ICS (tablet) and honeycomb (phone) and neither have crashing problems since loading Pro.
i'm running the demo version, and the only reason (well, two reasons) i haven't yet paid for pro are a. the constant crashing/freezing; b. the developer's unresponsiveness.
While I'm glad to hear that your version stopped crashing once you paid, this still makes me a little wary. Mind you, I have nothing against a developer getting paid for his work, and had the app said "you've used up your allowable demo time, please pay", that would be one thing. But for it to simply freeze up doesn't seem like a sign of a very competent developer. And the Android Play Store review boards are filled with flames against the developer. So I'm still holding out for an alternative! Thanks for your guidance, though.