I'm not sure that will work here; I'm running Apache 2.2. Older, sure, but completely capable of handling redirects correctly. If Apache 2.2 is too old, that needs to be listed as a system dependency up front.

I followed your guide. I ran the ubuntu installation script, followed the instructions for setting up the db, but even before then, the web app was redirect-looping with just those three RewriteRules in place. The REDIRECT_STATUS hack was the only thing that seemed to fix the initial looping but it's not catching the /auth/register loop.