TOPIC: Registered Users Issue

I found a solution to the same issue you mention.

I found that I did #3 as mentioned by dthadmin.

Go to the event.
Under the General tab you will see a box labeled "Prerequisite Events:"
If anything in that box is highlight you will need to un-highlight it.
(Use CTRL-click (or Command-click on a Mac) to de-select the prerequisite item.

I vaguely remembered inadvertently clicking on one of the items when I first created the event and was scrolling down the screen. I didn't realize that simply clicking on the event a second time DID NOT un-highlight it. Good thing I found this thread that mentioned how to un-highlight it.