This is much better than the post I had written, so here it goes.
You are unable to add an ESX Server to a cluster in the VMware High Availability (HA) configuration . This article provides you with steps to:
Troubleshoot an ESX Server that cannot be added to a cluster
Troubleshoot VMware HA configuration errors that are reported on the cluster and doing a Reconfigure for VMware HA has not resolved the error
There are a variety of error messages that are related to VMware HA configuration problems. For example, when VMware HA fails to start you receive the following error:
Note: This document assumes that you have already verified that you have enough licenses for VMware HA (and VMware DRS if it has been configured) for the ESX Server that you are trying to add to the cluster.