Check windows active sessions


I want to monitor the number of active sessions in our terminal servers (windows 2003) to see how many users are logged in.
Terminal servers have nsclient++ 0.3.8 installed and whit the others check_nt services all work fine.

From the shell I’ve tried whit this command:

But the result is always “0” (there are user on the terminal server instead).

How can I do?