Line 518 ff:

		for(int wn = 0; ret && wn < s.GetLength(); wn += n) {
			ret = WriteFile(hInputWrite, ~s + wn, s.GetLength(), &n, NULL);
			String ho = wreso;
			String he = wrese;
			wreso = wrese = Null;
			Read2(wreso, wrese);
			wreso = ho + wreso;
			wrese = ho + wrese;
		}

obviously last line should be wrese = he + wrese;

Same on line 538.

And I even don't understand why it was coded this way, it seems dangerous to give member variables (wreso, wrese) as parameters to the member function.
But perhaps there is a good reason for