Permission problem

When Try Qwinsta to Windows Server 2008 R2, it Give error 5. Which not happen to others server.
After some Study, Can try the command below.

Psexec.exe \\123.123.123.123 qwinsta

OR

runas /netonly /user:administrator "qwinsta /server:123.123.123.123" 
* which will prompt for the server password.

And Windows Server 2008 not allow to remote to physical console anymore, no wonder how u connect it will not connect to session 0 (which reservce for service used).
But for your infor, for some of the purpose, you might need to use /admin (or /console) for the connection.