Thank you athena, that was the problem. Actually my template had the order_steps_defines.php as well, so that was overriding the one in the extra_definitions.

That did get me through that part, but even after spending hours on it, I still was having problems so I removed it again. Is this the best solution for checking out without an account? I don't know why I'm having such a block with this one. I don't like being beat by a plugin, but I want to make it easier for customers to check out.