As the title suggests 
Help appreciated. I am registered and have a valid (just purchased) NEXT install.
I had the same problem. I emailed sales@chaosgroup.com and they fixed it for me. Mention your username in question and your order number.
Thanks. I expect someone will reply tomorrow when (normal) people are working
You can also email us at support@chaosgroup.com with your forum name and our support team will enable posting for you.
Best regards,
Vlado