The alien tells the human to move his finger due east on the star chart, however in space there are no normal compass-based directions since these relate to a planet while on the planet. The alien could have said left or right and been correct.
Alan is having a discussion over radio signals with the Galaxy Being who is located in the Andromeda Galaxy. Radio waves, like all electromagnetic waves, travel at the speed of light. Since the Andromeda Galaxy is 2.5 million light years away, it would have taken any single radio messages 2.5 million years to go one direction, making any communication impossible.