If you're using the default ports of 48650 and 48651 for the Session Central Service and Session Service, with Runtime Service using port 443, are you also installing the Service Based Architecture (SBA) components which also has 3 services or so of its own, that use different port numbers, and if so, is one of them attempting to use port 48665 which is being used by something else?
SBA has two URL reservations that will use that port > http://+:48665/Control and http://+48665/DS
On the server you're installing Web Client onto and getting this message, open a Command Prompt: Admin window and type in the following:
netsh http show urlacl
This will show you all the URL reservations setup on the server. You should see one for the Session Service, Session Central Service and Runtime Service for Web Client. You also may see other reservations with port 443 which is fine, as that is the default SSL port number, but you shouldn't see multiple reservations for non-443 port numbers.
In this list, look for what is using port 48665 and if something valid already is, try using a different port number than port 48665 for the SBA components when installing.
**NOTE: If you don't actually plan on using SBA, you can remove it from the features to be installed, when installing the Web Components, leaving only Web Client to be installed.
Thank you,
