D'oh! I figured it out...
Instead of <?, I need to use <?php in the php script. Apparently, the apache2/php installation tolerates this and the nginx/php5-fpm does not. Once this edit was done, the web page works on port 88.
To fix the libav error, I renamed the soft link to libav_old.so and installed motion. It then I got the motion video stream on 4040 and then everything 'just worked'.
I'll have rune on the garage controller this w/e.
Keith