I'm very annoyed with SELinux today. I've just figured out that the reason I was getting very mysterious access denied errors was that I hadn't done the magical incantation:

chcon -R -t httpd_user_content_t the_dir_to_show_in_apache

which allows the use of those directories in the HTTP context.

Hey, it's my first brush with SELinux… Anyway, I'm glad I got that
sorted out, although it took me slightly over half an hour to figure
that out and get Twiki up and running. Mrph.

Next step: Kerberos authentication.