Have you verified the ESXi firewall configuration? I had the same issue and found that the firewall rule "vprobeServer" (poty 57007) was either open or closed. Do you have the firewall rule at all on all your ESXi hosts?
Should look like the below in the esx.conf file inte the /etc/vmware directory:
/etc/vmware/esx.conf:/firewall/services/vprobeServer/allowedall = "X"
/etc/vmware/esx.conf:/firewall/services/vprobeServer/enabled = "X"
X is either true or false.
//Magnus
