Windows 2003 Cluster Service account Problem

We recently set up a 2 node active/passive cluster. We subsequently decided to change the service account from one in the local chiuld domain to one in the parent domain (root). Following the recommended practices from Microsoft, I changed the account successfully. The one issue we are having is that The network names of cluster resources can not be brought online if we Enable Kerberos Authentication.It works fine if this is unckecked. The parent domain service account has user rights to the parent and is a member of the administrator group on the local child domain. Please assist. I cannot figure this one out.