Issue building a 5.5 test environment

Im trying to build a test environment with 5.5 and having an issue installing vCenter on a VM.

The host is a ML110 G7 and has plenty of disks and RAM.

I have ESX 5.5 installed on it and it works fine.

I have two win 2008 r2 VMs setup and they work fine too.

I have no AD / DHCP or DNS server configured.

The issue I have is that when I go to install vcenter it rolls back on SSO.

I cant get it to go past SSO.

Any one any idea what might be causing this.

Does vCenter require AD/DNS or is there any other requirements when vcenter is installed on a standalone system on a VM.