First, be sure to eliminate this issue: http://stackoverflow.com/a/4975210
Next, enable logging of all events. That will save you plenty of time.
If you are using nginx, be sure to include correct fastcgi configuration file: http://softwaremaniacs.org/forum/django/9093/ (post before the last). Fairly equal to http://serverfault.com/a/229188. But extensive configuration http://stackoverflow.com/a/605196 didn’t work for me.