Raulo, you have a mathematical error on page 1, in equation (4).

Your \xi depends on n. Consequently, you cannot pass to limit only in part of the expression.

The expression q:=1- (1/2^32* D)  is a real number < 1. Consequently, Q(n)=q^n -->0 as n --> \infty.

This makes perfect sense, because the probability that you will "almost surely" (in the sense of probability theory) find a block if you wait long enough (infinitely long).