I was just creating some events (JEvents 1.5.2 / DTRegister 2.6.1 / Joomla 1.5) and thought I'd copy an event I'd just created in DTRegister. The original event was created normally, meaning nothing out of the ordinary. Upon completion of that event, I put a check mark next to it in the DTRegister Event list, then clicked the 'Copy Event' button up top. When I did, I got this message:
Prerequisite Categories:
Fatal error: Call to undefined method stdClass::get_prerequisite_category() in /path/to/joomla/administrator/components/com_dtregister/view/events/newgroup.php on line 482
I was able to reproduce this message. I can work around this error so it's not a high priority for me, but wanted to pass it along.
We have just updated the package to 2.6.2 with a number of fixes and a couple new items. Official announcement is coming shortly. You can download it now from My Orders and you'll find this copy event issue fix is included.