Take a look at this page: http://diecaststuff.com/YoungLiving-Events/2015/03/introduction-to-essential-oils/
Now click on the see who has RSVPed at the top and then click either of the images. Why are these links going to a blank page?
The same issue was happening with the Event bread crumbs so I disabled them to eliminate the issue, but I would rather have the issue fixed so it is working properly.
I also have not received a response to my post about not getting WHMCS working properly. An update on that would be nice.