running xen

I have been playing around with xen a little on my Centos 5.1x64 machine however if I run a virtual machine it seems to always have a runaway binfmt problem (tried to modprobe binfmt and goes into a loop and eats cpu bad).

Maybe it has to do with my hardware (amd X2 5000, 4gb ram) Centos 64? I can find a lot of references to the problem on the net but no solutions.

Any ideas?

Fred B.