I'm having same problem here.
I'm not surprised either of you is having problems creating a new output module and making it the default. That's not where you do it.
Go to Edit>Templates>Output Module. Make a new one. Select one to use as a default. Select a different one if you want a different default. You can have a default for both stills and movies. You can do the same thing for Render Settings. It's the same basic drill.
Since this is basic AE 101-type stuff, I bet you'd get a lot out of these how-to's from the pros: