Your ticket has been resolved but for others reading this...
We have discovered that this problem was due to your own modifications. You apparently had upgraded from DT Register 2.5.2 and then reloaded your old dtregister.php file from that version into the 2.5.8 version. You can't do that. That older version did not have the code to trigger our newer plugins. That was added in 2.5.7 so you had made a situation that would never have worked. I backed up your version, then reloaded the current dtregister.php file and all is working just fine. If you make modifications, you have to re-apply those to NEW versions of the file. You can never just reload your older modified version. It will not work.