I am running vSphere 4 (vCenter 4 with ESX 4) and have a Red Hat Enterprise Linux 5 VM. The I have installed VMware tools on this VM. The summary tab in vCenter shows the VMware tools status is OK. When I try to migrate the VM to another host I get the following: "No guest OS heartbeats are being received. Either the guest OS is not responding or VMware tools is not configured properly."