I have read the thread at http://www.zen-cart.com/forum/showth..._group_pricing
And DrByte's post #10

Seeing this type of error during checkout when applying a coupon and getting:
Warning: Division by zero in /includes/modules/order_total/ot_coupon.php on line 365
Code at 365
Code:
$ratioTax = $adjustedTax/$order->info['tax'];
Any insight as to where in this file would a correction be applied and what would it be?