client 5.5 accessing 5.0 host.

I'm trying to connect to a 5.0 ESXi host with vsphere client 5.5.  When I attempt to do so I get a pop box that says I have to download client files.  gives me a URL of vsphereclient.VMware.com.  this machine does not have access to the internet.  plus, I should be able to connect to a 5.0 host with 5.5 client.  See attached for dialog box.  anyone have an answer to the issue?