[CentOS] XFS install issue

I am attempting to implement XFS on a new system.

System:
Supermicro SC846 TQ-R900B - rack-mountable
SUPERMICRO X7DWN+ - motherboard
3ware 9650SE-24M8 - storage controller
10 Hitachi DeskStar 7K1000 - hard drive - 1 TB
8GB Ram
2 Intel Quad-Core Xeon E5420 / 2.5 GHz processor

Installed Centos 5.1 X86 64 from DVD. System on /dev/sda1 
– 250GB ext3 (raid 5). /home will be on /dev/sdb1 – over 
7TB XFS.

Kernel version issue

---------------------------------
  
[root at csfs50 work]# yum install kmod-xfs.x86_64
Loading "installonlyn" plugin
Setting up Install Process
Setting up repositories
Reading repository metadata in from local files
Parsing package install arguments
Resolving Dependencies
--> Populating transaction set with selected packages. 
Please wait.
---> Downloading header for kmod-xfs to pack into 
transaction set.
kmod-xfs-0.4-1.2.6.18_53. 100% |=========================| 
2.8 kB    00:00
---> Package kmod-xfs.x86_64 0:0.4-1.2.6.18_53.1.19.el5 
set to be installed
--> Running transaction check
--> Processing Dependency: kernel-x86_64 = 
2.6.18-53.1.19.el5 for package: kmod-xfs
--> Restarting Dependency Resolution with new changes.
--> Populating transaction set with selected packages. 
Please wait.
---> Downloading header for kernel to pack into 
transaction set.
kernel-2.6.18-53.1.19.el5 100% |=========================| 
256 kB    00:00
---> Package kernel.x86_64 0:2.6.18-53.1.19.el5 set to be 
installed
--> Running transaction check

Dependencies Resolved

=============================================================================
  Package                 Arch       Version 
         Repository        Size
=============================================================================
Installing:
  kmod-xfs                x86_64 
    0.4-1.2.6.18_53.1.19.el5  extras            253 k
Installing for dependencies:
  kernel                  x86_64     2.6.18-53.1.19.el5 
 updates            15 M

Transaction Summary
=============================================================================
Install      2 Package(s)
Update       0 Package(s)
Remove       0 Package(s)

Total download size: 16 M
Is this ok [y/N]: y
Downloading Packages:
(1/2): kmod-xfs-0.4-1.2.6 100% |=========================| 
253 kB    00:00
(2/2): kernel-2.6.18-53.1 100% |=========================| 
 15 MB    00:02
Running Transaction Test
Finished Transaction Test


Transaction Check Error:
   package kernel-2.6.18-53.1.21.el5 (which is newer than 
kernel-2.6.18-53.1.19.el5) is already installed

Error Summary
-------------