SuSE 9.3 + XEN + IBM x306 = lockup

Hi List, I've just installed SuSE 9.3 (x86_64) on my brand spanking new IBM x306. This machine has a EM64T Pentium4 processor. The installation went ok, and I pulled down all the updates via online update. However, I cannot boot the XEN kernel. When I try booting this kernel, it locks up hard after the boot message 'NET: Registered protocol family 16'. The only means of recovery from this is to hit the reset button. Booting the normal kernel is fine. I'd really like to run some XEN guests on this machine, so any suggestions will be very gratefully received. The XEN kernel is (updated through YOU) kernel-xen-2.6.11.4-21.9 Cheers, Richard