[CentOS] dd disk will not boot - can't find /dev/root

Mon Dec 12 15:51:10 UTC 2011
Joseph Spenner <joseph85750 at yahoo.com>

OS= CentOS 5.4, 64bit.

I've always had great luck using dd to copy entire disks, and booting on other systems.  However, I'm having difficulty with a couple systems.  I boot using an install DVD so the OS disk is quiet, and dd to my target disk:

# dd if=/dev/sda of=/dev/sdb bs=1024k

/dev/sdb is the blank disk.  The disks are 2T.  After a few hours the operation is complete.  But when I try to boot the new disk on my other system, I get the following errors after the CentOS boot menu (it counts down to boot the default disk fine, then this error):

  (screen shot at   http://img214.imageshack.us/img214/645/centosbooterror.jpg   )

I've read posts regarding the /dev/root error, and they talk about rebuilding initrd.  I've tried some of the fixes mentioned, but have had no success.
All I can think of is slightly different hardware on the new system where I'm trying to boot, but I'm not sure what the difference could be.
They're both 64bit SuperMicro systems.

If anyone has any ideas, I'd love to hear.