TOPIC: Discount Code Error

Hi I have Updated to DT Register 2.7.12 for Joomla 1.5
My PHP. ini had 64 now 128 MB.
My Joomla installation is 1.5.25
Im Using Kunena 1.6.4, JoomSocial 2.4.1, JoomGalery 1.5.7.4 and Remository 3.53.13J as major Components.

First of all I don't see the Discount Code in the registration workflow. I created on. In this one i set it for all events.
In the event I checked the code and selected use discount code to yes.
Anyways there isn't a field showing up on registration. When i now try to add the code afterwords in admin page i get following errors and returning back to overview without any changes:
Notice: Undefined property: TableDuser::$process in ... /administrator/components/com_dtregister/lib/dtfee.php on line 90
Notice: Undefined property: TableDuser::$fee in ... /administrator/components/com_dtregister/lib/dtfee.php on line 603
Notice: Undefined index: latefee in .../administrator/components/com_dtregister/lib/dtfee.php on line 604
Notice: Undefined index: birddiscount in .../administrator/components/com_dtregister/lib/dtfee.php on line 660
Notice: Undefined index: memberdiscount in .../administrator/components/com_dtregister/lib/dtfee.php on line 323
Notice: Undefined index: memtot in .../administrator/components/com_dtregister/lib/dtfee.php on line 1780