I just switched to a guest user account and was able to connect to the IndigoServer running on my admin account. I choose the Indigo 2->Connect To Remote Server... menu item. I used the IP address 127.0.0.1, it connected and let me control devices. Any idea what may be different on your setup? I'm running OS X 10.4.8.
After I switch users, Indigo seem to respond to switch events. However, after I let it set overnight Indigo does not activiate timed events. Also, I might have something else wrong as I can not SSH into it right now.
I am also running 10.4.8.
I'll post more after I see what is happening.