Hey Jack,
I feel quite silly right now, you are correct - I hit the error once, then instead of going back to my example I just kept refreshing the page - thinking the error would go away, but at that point it navigated me away from my example. My apologies for wasting your time.
To not make this a complete waste, one thing I did notice on the error page is that the 'account dashboard' link points to: https://greensock.com/forums/account-dashboard - looks like it might be an error.
Thanks, and sorry again,
Mariusz