Losing Remote Connection

I am using Vista Business on Home Desktop machine and also on laptop. I have
set up remote desktop connections and am using them successfully, however,

After I finish my session I click disconnect at the top of the screen and
the session ends. Then when I try to reconnect, it tells me the remote
computer is not available - Try connecting again. If the problem continues,
contact the owner of the remote computer or your network admin. ( I love
that, I am the network admin)

If I have my wife reboot the remote machine, then I can connect again
successfully. but the cycle starts all over again.

I seems something isn't getting closed properly on the remote machine. Any
ideas on where to begin to look

????

Paul