Theology's definition of divine omniscience is that God is all-knowing, aware of all things that have happened, are happening and will happen. mjs asserts that therefore, God knows every true statement. Now, let's take the statement "God does not know this statement."
An omniscient God will know this statement. Therefore, the statement itself is false. Despite what mjs says, the fact that God knows this statement has no effect on whether or not the statement itself is true. God knows all statements, both true and false. It's not necessary for God to believe a statement is true in order to know it.
The basic assertion (mjs' definition of "knowing a statement") is false, so the argument is a fallacy. Godel's Theorem doesn't even come into play.