Actually, I can't use the Impulse chat from Impulse either (says connection refused) but here's what happens in Demigod:
- I press shift-tab to get the menu, but if this is during the intro, I get no mouse cursor (even though it's clearly active).
- I press chat and get the window and type /channel demigod... and nothing happens... nada.
I am able to connect to Stardock irc via Mirc and Impulse was able to download Demigod, and also, I was able to play the game online, so there are no problems with my internet connection. Just chat within Impulse/Demigod.