I am setting up a virtual environment to host Project Server 2010 beta. Using VirtualBox I created a domain controller, SQL server and application / web server. All 3 machines are running windows server 2008 r2. When I try to connect the SQL or application / web servers to the domain controller I get the following error "An attempt to resolve the DNS name of a domain controller in the domain being joined has failed." I am able to ping both clients to the domain contolller and vica versa using both ip addresses and names. Can you shed some light on this.