Looks like this thread has been dead a while, but I think I see what your problem is in case you are still not working. Look back at their pic showing where all of the blue shorts and the jumpers are located. Next to the right cap connection, you will notice a blue short that your are supposed to make. I missed this when I made mine and had the same issues. If you test the thing you will notice that the right channel is a full volt lower than the left, and the cap for that side next to the blue short is doing nearly nothing.
Just jam a wire in there and solder it in, I suspect your opamp is fine (assuming you didn't really try it out backwards).
Also, their diagram is correct, but both of their pictures are incorrect. The short I am talking about is only shown in the diagram, not in either picture. You can even see it obviously missing in their pic of the bottom of the board. They are the only un-soldered dots on the thing directly next to each other.
Edited by Pedantyc - 9/25/11 at 8:28pm