Aha, I found the logs in log/production.log and found the session permission error. Removing all the sessions and making sure that the session directory is writable cleared up my problem. If anyone else reads this, here is what I learned:
1. Logs are in your-app-directory/logs one for each of the environments, production, development, test
2. Sessions are stored in your-app-directory/tmp/sessions
2. Switching back and forth between WEBrick and Apache requires that you clear your sessions or you will get a "stale session" error reported in the log file or you will get a permission error.
4. The http 500 error page says, "Sorry, something went wrong."
Also I learned that it is dead simple to switch from SQLite to MySQL in Rails, it is pretty easy to switch to Apache if you are running other non-ruby apps.
Thanks to Radar, you were right on.