Are you using the new vox-l simulator? The old simulator hasn't been updated - we're planning to do away with it eventually.
When you go to http://mod.learntomod.com/badge_pointers/public did you select the 'skills and drills' icon at the top of the page? That's the new vox-l interface. The old interface (in which the simulator doesn't work)is at the very bottom of the badge index page. If you're using the old interface, we recommend scrolling to the bottom of the badge instructions and pressing the skip simulator button.
You shouldn't have to enter a Learntomod nickname when connecting or do anything - that used to be the case, but the software has been redesigned. Can I ask where you saw that you had to do that? If a user is concerned that they might have gotten opped out of their minecraft world, they can always enter their minecraft username in the Account gear section of Learntomod - is that what you meant?
Is the vox-l simulator not loading at all?