1. What version of Windchill? 10.1 or 10.2?
2. Do you have Creo installed in this client? If yes, which version and maintenance release of Creo?
3. If using Creo, have you configured it to use this Windchill server (resister new server, set as Primary server) and workspace using the "CAD CONTRIUTOR" user?
4. If yes to question 3, when to open Creo File-->Manage Session-->Server Management, In the Sever Management GUI, on the Servers tab, in the Servers Window, for your Windchill Server, in the Status column, does it say "Offline"? If yes, right click on that line in the Server Manager GUI, and remove the check mark from the "Work Offine" check mark.