Sorry for the delay angekay. There is not a method of setting one payment method as automatically selected. However you should not be able to proceed without selecting an option. Not sure how someone got through because we can not replicate that. Anyway...
First, make sure you are using the latest release, which is currently 2.3.7. Then open this file:
/components/com_dtregister/dtregister.php
Around line 6482 you\'ll find this:
<input type=\"radio\" id=\"paymentmethod\" name=\"paymentmethod\" value=\"paypal\"><?php echo PAYPAL;?>
Replace this code with:
<input type=\"radio\" id=\"paymentmethod\" checked=\"checked\" name=\"paymentmethod\" value=\"paypal\"><?php echo PAYPAL;?>
That will made PayPal the default payment choice.
Regarding changing the text for \"Total Registration Cost\", it IS in the language file. It shows like this:
define(\"TOTAL_REGISTRATION_COST\",\"Your total Registration cost\");
Thanks