Thanks for the response. The vCenter Inventory Service is running and shows healthy in the vCenter Service Status. All of the vCenter components are installed on the same server (using vCenter Server 5.1 build 1123961) and, for now, the Windows firewall is off. I get the same error when running the VI client from the vCenter server and, although, I am able to open the URL, I am not sure I should see this when the page loads:

HTTP Status 400 - Bad request

type Status report

messageBad request

descriptionThe request sent by the client was syntactically incorrect.

VMware vFabric tc Runtime 2.8.1.RELEASE/7.0.32.B.RELEASE

Should it show me something a little more encouraging? I have nothing else to compare the result with!