I just reinstalled the plugin and it’s working fine. I’m running wordpress 3.7.
Can you take a screen shot and email it to me? Also, can you do this in firefox while running firebug. That way I can see what sort of errors you are getting.
Feel free to contact me directly, here.
Also, you need to add a course first. After clicking the add course button, a module should pop-up asking for information about the course like name, etc… Once the course is added, click on it so that it becomes highlighted orange. Then you can start adding students.
Please let me know if this works.