Their response:
Thank you for contacting us.
After receiving your email and the information provided, a review of the software and the tournament in question has been completed and we do not encounter any issues on our end that could lead to a reason for your situation.
Also we can confirm that other players have been able to register without any issues.
If the problem persist please lets us know. Also in such case, please provide us with your computer specifications to further investigate.
Their website:
I call BS. Their customer service is 3rd nut low.