Why doesn't the kdump service start while running kernel-xen kernel?

Issue

After I configure kdump, I try to start the services but get the following error:

    # service kdump start
    No kdump kernel image found.                               [WARNING]
    Tried to locate /boot/vmlinuz-2.6.18-164.el5
    Starting kdump:                                            [FAILED]

And I am using a xen kernel:

    # uname -r
    2.6.18-164.el5xen

• Found following error messages in system log(Used kernel  2.6.18-274.12.1.el5xen) :

Dec 24 07:11:43 hostname kdump: Cannot open `/boot/vmlinuz-2.6.18-274.12.1.el5PAE': stream error  
Dec 24 07:11:43 hostname kdump: kexec: failed to load kdump kernel  
Dec 24 07:11:43 hostname kdump: failed to start up