[CentOS] kernel source

Hi,

I am trying to install the kernel src rpm that I've downloaded from the 
CentOS ftp, kernel-2.6.9-22.EL.src.rpm. I hope to compile the kernel 
with XFS enabled. However, I have tried to simply run:

[root at se4 ~]# rpm -iv kernel-2.6.9-22.EL.src.rpm

and it complains back:

warning: group builder does not exist - using root
warning: user builder does not exist - using root
warning: group builder does not exist - using root
warning: user builder does not exist - using root
warning: group builder does not exist - using root
warning: user builder does not exist - using root
....

then an rpm -q kernel-2.6.9-22.EL.src.rpm says:
package kernel-2.6.9-22.EL.src.rpm is not installed

Anyone know what is going on??

ps. I have tried to install the CentOSplus kernel with xfs and that is 
completely unstable for me.

thanks,
Andrew