I'm running Fedora 9, using cobbler 1.4.1 that yum retrieved for me from the Fedora updates repository. SELinux is denying tftpd access to vmlinuz-PAE. This is in my /var/log/messages many times:
setroubleshoot: SELinux is preventing in.tftpd (tftpd_t) "read" to ./vmlinuz-PAE (httpd_sys_content_t)
By the way, SELinux also prevents dhcpd and tffpd from writing to /var/log/cobbler/cobbler.log. I'm not sure I'm in the mood to learn how to write SELinux policy so I'm going to turn off SELinux enforcement and try again.
Tim