I tested on my machine using both hostname based multi sites and folder based multi sites and it works as expected in both cases.
So I can only guess its some configuration or permission issue if its not working on your machine.
Are you seeing any errors in the log related to writing the index?
Do you have any virtual directory mappings beneath the root of the mojoportal site or anything like that going on in your installation or anything different about your environment that you haven't mentioned?
Best,
Joe