What could be causing this error:

$ sudo tail -n 100 /var/log/apache2/error.log'

[Wed Dec 29 15:20:03 2010] [error] [client 220.181.108.181] mod_wsgi (pid=20343): Exception occurred processing WSGI script '/home/username/public_html/idm.wsgi'.  
[Wed Dec 29 15:20:03 2010] [error] [client 220.181.108.181] IOError: failed to write data  

Here is the WSGI script:

$ cat public_html/idm.wsgi 
import os
import sys

sys.path.append('/home/username/public_html/IDM_app/')

os.environ['DJANGO_SETTINGS_MODULE'] = 'settings'

import django.core.handlers.wsgi

application = django.core.handlers.wsgi.WSGIHandler()

Why would Django not be able to write data?

I'm running Django 1.2.4