Hi
Many thanks for the reply.
No I did not perform this step as per the guide:
You have the following options:
■ If you are upgrading from vCenter Server 5.0 to vCenter Server 5.1 Update 1, continue with Step 2.
■ If you are upgrading from vCenter Server 5.1 to vCenter Server 5.1 Update 1, go to Step 3.
I go to step 3 (skipping step 2) as I am upgrading 5.1 to 5.1 update 1
regards
Ciarán