Kernel panic after update

Hello;
After updating the kernel to version: kernel-2.6.18-416.el5 (Redhat 5), and rebooting the server, i got a kernel panic error, and the system failed to boot.
This server is a virtual machine on Hyper-v. This version of the kernel worked fine on all the other VMs on Redhat 5.
Can you help me diagnostic this problem?
Thank you
Regards