Are you getting any bubbles at all in the skimmer body? If not, either the venturi is clogged or the air valve is shut. If you are getting bubbles in the skimmer body, and it's overflowing, the air may be turned up too high. IME, Berlins tend to "run away" for a few days after you start them up. They are great skimmers though and will do you a good job once you get it adjusted.
Life is not measured by the number of breaths we take, but by the moments that take our breath away.