Confirm that it's the redirect stage that's causing the problem by replacing
HttpResponseRedirect(url)
with
HttpResponse('<!DOCTYPE html><html><head><title>title</title></head><body><a href="%(url)s">%(url)s</a></body></html>' % {'url':url})
If this doesn't render, then the problem is happening before the redirect. If it does render, then the problem may be the redirect, or it may be the redirected page. Click on the link. If the next page displays correctly, the problem is almost certainly the redirect itself. Otherwise, the problem is in the redirected page.
Jordan Reiter
2010-08-27 19:18:46