invalid or unsupported executable format

[Ken Dyke <kdyke@keycomputerconsultants.com>]

Default Fedora Core 5 "server profile" with SELinux disabled.
Downloaded from:
http://bits.xensource.com/oss-xen/release/3.0.4-1/kernel-3.0.4-fc5/RPMS/i386/

        xen-3.0.4.1-1.i386.rpm
        kernel-xen-2.6.16.33-3.0.4.1.i386.rpm
        xen-devel-3.0.4.1-1.i386.rpm

Installed the rpms and updated grub.conf, then reboot...
grub reports:

  Error 13: Invalid or unsupported executable format


So, I tried building from (downloaded from above URL):

        xen-3.0.4.1-1.src.rpm

which resulted in:

RPM build errors:
    File not found:
/var/tmp/xen-3.0.4.1-3.0.4.1-0603ab5b0ede.bb101e77d4a3-root/etc/hotplug/xen-backend.agent


So, I downloaded the source tarball.  Built that and ended up back at
the grub error:

  Error 13: Invalid or unsupported executable format

One would assume that since FC5 binaries are being made available
someone it running xen on FC5.  So, what am I doing wrong?
-- 
Ken Dyke,
406.581.0495

"Linux can win as long as services/protocols are commodities.  By folding
extended functionality into today's commodity services and creating new
protocols, we raise the bar and change the rules of the game."
       -- from an internal Microsoft memo