On p. 28 l. -10: Say "bounded open connected set (bounded domain)" instead of "open bounded set". This assumption is required for the Poincare's inequality to hold. It is clear that this assuption of connectness can be relaxed; The point is not to allow $\Omega$ have a component $\Omega'$, such that $\partial \Omega' \subset \Gamma_1$.
On p. 29 l. -11: Remove the sentence starting "In the same manner...". Its proof is wrong, the statement is untrue, and it is never used anywhere.
There is letter $h$ in many formulas on p. 29 -- 30. It should be $z_0$.
There is a number of typos etc. all over the paper that I will not try to correct here.