django flatpages works with DEBUG=True, doesn't work with DEBUG=False
When debug is set to False django renders the 500.html template instead of the debug stack-trace thing.
It might be that on a http 404 (not found) exception it tries to render the 404.html template and if it's not found than tries with the 500.html (internal error).
It is not a problem in itself but just a configuration.
I can see that django looks for 500.html when DEBUG is False.  What could be the problem?