The enforcing SELinux feature in Fedora Core 4 may block the root user's attempts to use the aoe block devices in /dev/etherd. The Fedora Core 4 release notes mention SELinux:
http://fedora.redhat.com/docs/release-notes/fc4/
... and more detailed information is found at the SELinux FAQ for Fedora Core here:
http://fedora.redhat.com/docs/selinux-faq/
Although FC4 is not listed there, the information provided for FC3 should help you to configure or deactivate SELinux as you see fit, especially, this question:
http://fedora.redhat.com/docs/selinux-faq-fc3/index.html#id2825232
... which you can use to set the SELinux policy to "permissive" (skip step 6) if that's what you decide to do.