Monitoring ESX 4.1 with Nagios XI

We are running Nagios XI 2012R1.1 and are trying to monitor our ESX 4.1 hosts.

I ran the Nagios XI vmware monitoring wizard but I can't seem to get Nagios XI to monitor a vmware ESX 4.1 host service (i.e CPU utilization) unless I use the ESX root account and password on the ESX host?

I tried creating a new account called "v_nagios" on the ESX host using the VMware vSphere Client, but when it tries to monitor a service, I get an error:

                                         ESX3 CRITICAL - Error: Permission to perform this operation was denied.

From the ESX logs, it looks like the account is getting logged onto the host.

I have applied the following groups to the "v_nagios" account: adm, bin, daemon, root, sys

I have also granted shell access to the "v_nagios" account.

Gene