Re: System.Exception on loading Default.aspx
You are using the 2.x branch of mojoportal right? I am getting the same error on my dev site at http://dev.mojoportal.com
Some recent changes in mono svn broke things that were previously working.
I'm afraid the 2.x branch of mojo under mono is not viable at the moment. I am only recommending the 2.x branch of mojoportal for windows for now until a release version of mono works with it. mono from svn is not feature complete for 2.0 .net features and there will be bugs to work through.
I will try and pin down the cause of this particular error this weekend and report it.