Zero Sum error: can't read protected property

Having an issue with Zero Sum.
Everything worked perfectly until yesterday.
Now my python code is invalid to some strange problem:
TypeError: Can’t read protected property: findEnemyMissiles
The problem is in this line:

missiles = self.findByType("shell", self.findEnemyMissiles())

Before that day everything worked flawlessly.
Why does this problem appears?

It looks like an issue in the new interpreter (Esper). See this related thread where @nick has replied.

Ah, found the bug! Will deploy the fix shortly. Thanks for posting that one.

Yep, that’s solved.
Now it throws out another error:
TypeError: Statement execution limit reached.