Good afternoon )
Not 100% remembering a similar issue but it could be to do with using IP rather than FQDN.. Just a hunch..
Hi,
Follow this article step-by-step. You won't get any error...
http://derek858.blogspot.com/2012/09/vmware-vcenter-51-installation-part-1.html
It has 15 parts showing different ways to install SSO, VC web client, etc.
Thanks-AG