Last time, I mentioned one way to TS to server even there are already two connections there, what you need is to cancel the disconnected or unactive session, you can find that article from here.
Well, from my experience, there is another way to get connected under the same situation, that’s because in Windows Server 2003, when you use Terminal Services, you can connect to the console session (session 0), and at the same time, open a shadow session to it (as long as you connect from a session other than the console). With this added functionality, you can log on to a Windows Server 2003-based server that is running Terminal Services remotely and interact with session 0 as if you were sitting at the physical console of the computer. This session can also be shadowed so that the remote user and the local user at the physical console can see and interact with the same session.
To connect from the remote Windows Server 2003-based computer, open a command prompt, and then type the following command:
mstsc -v:usssprodweb01 /f -console