Why adding RHEL5 hypervisor to RHEV-M fails with "ERROR Unable to fetch vdsm22 package."?

Issue

• While trying to add RHEL5.6 based machine to RHEV-M as a hypervisor, it fails with the below error message in /tmp/vds_bootstrap.xxxxx.log.

  Fri, 13 May 2011 17:43:13 DEBUG    yumSearch: package vdsm22 not found!
  Fri, 13 May 2011 17:43:13 ERROR    Unable to fetch vdsm22 package. Please check if host is registered to RHN, Satellite or other yum repository
  Fri, 13 May 2011 17:43:13 DEBUG    <BSTRAP component='RHN_REGISTRATION' status='FAIL' message='Unable to fetch vdsm22 package. Please check if host is registered to RHN, Satellite or other yum repository'/>