For us sciency wannabe's Douglas Axe keeps it simple:
When Theory and Experiment Collide
Even if Axe's results are correct, I'm not sure this rules out Mike Gene's front-loading hypothesis. What if we discover that all the supposedly new protein folds actually are quite ancient? Then it seems possible that they were part of the original design at the origin of life, and that the Darwinian process had them at its disposal for future evolution.
Update: The paper that the "simple" explanation is based on: here.