Apologies.
The UCS is in beta. It's got a few problems. The DEFAULT set, for instance does not allow you to view or edit the cards (with this release, anyway).
So, yes, you need to load someone's template to view the cards. DennisB's set was done in Beta 2. If you'd like to use his template, you need to open his STYLE file and change the following:
change 'class race' to 'classification'.
change 'power type' to 'type'.
change 'card name' to 'name'.
Once you save this, it should load just fine in MSE.
Unfortunately, this is what happens with Beta software / projects - things are changed and break.
Once we release the first actual 'working' version you shouldn't see issues like this cropping up.
-- Hirahito