Oops, sorry about that; I thought you meant to simply add "debug" to the log
directive in the .conf.

But! I updated to 0.8.31 and rebuilt with --with-debug (as per your
recommendation) and everything works perfectly.

Here's my final nginx.conf if anyone else will want to do something similar in
the future.

       location /eve/ {            proxy_pass http://127.0.0.1:9001;            proxy_intercept_errors on;            error_page 504 = @fallback;        }

       location @fallback {              rewrite  ^(.*)$  /backend.php;        }

Kind of a messy rewrite, but for my purposes, it's fine. Thanks for all the
help, and happy 2010 =)

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,36944,36998#msg-36998