Cups' docroot is defined as $PREFIX/share/cups/doc. Files it normally has there (like cups.css) are in /usr/share/doc/cups-1.1.1 in the RPM. Because of this, the web admin interface doesn't work. This can be fixed in two ways: either define DocumentRoot in /etc/cups/cupsd.conf, or modify the configure script (which hardcodes the location). Unfortunately, there are no options one can pass to configure to change this.
It's fixed in cups-1.1.4-1. You find it in rawhide soon.