Why does a Dell PE6800 system encounter a kernel panic when doing a PXE-install with Red Hat Enterprise Linux 4 Update 4 on an x86-64 kernel?

Release Found: Red Hat Enterprise Linux 4 Update 4

Symptom:

A kernel panic that looks like the following snippet occurs:

Kernel BUG at apic:305
invalid operand: 0000 [1]
CPU 0
Modules linked in:
Pid: 1, comm: swapper Not tainted 2.6.9-40.EL
RIP: 0010:[] {setup_local_APIC+27}
RSP: 0000:000001007f763ef8  EFLAGS: 00010246
RAX: 0000000...