I saw the thread about the error:
Fatal error: Method name must be a string in /home/nawboclv/public_html/cms/components/com_dtregister/controllers/payment.php on line 104
from March 2012. it shows as solved, and references fixes in 2.7.15a.
but i have one user who is getting this error and we are on 2.7.16a.
We've had 10 other users successfully register for the same event, and i am trying to get further details about what this user might have done differently.
You just need to update. There were various issues that floated through 2.7.15 and 2.7.16 that took a bit to completely nail down for all cases. You should update anyway
Login, and go to My Orders. When you see your order listed, there will be a Download link to the right IF your license is still active. You have access to downloads and support for one year from purchase. If the license is expired, you'll need to purchase another license to get another year of updates.
i've upgraded, and things seem to be working, though received an error about the SSL Certificate when going to the Calendar view, even though the certificate is up to date.