The .bat looks fine, and I'm pretty sure the error messages in the CGminer screenshot are just because the Cube's IP is skrewy.
The failure is on the USB port but that is not used for the cube.
The main question: Is the proxy address and port on the cube correct, that is do they match the proxy computer. Is there something that is blocking the communications initiated by the cube to the proxy being blocked, either IP Address or port?