Hi! just found some untranslated string constants in cart.php helper 
On line 1224		if($userAttempts>0 and ( !empty($coupon_details->virtuemart_coupon_max_attempt_per_user) and $coupon_details->virtuemart_coupon_max_attempt_per_user>0 )) {
			if($userAttempts>=$coupon_details->virtuemart_coupon_max_attempt_per_user) {
				$this->couponCode = '';
				return 'Maximum coupon usage limit reached, please try different code.';
			}
		}Should be		if($userAttempts>0 and ( !empty($coupon_details->virtuemart_coupon_max_attempt_per_user) and $coupon_details->virtuemart_coupon_max_attempt_per_user>0 )) {
			if($userAttempts>=$coupon_details->virtuemart_coupon_max_attempt_per_user) {
				$this->couponCode = '';
                return vmText::_('COM_VIRTUEMART_COUPON_CODE_MAX_USAGE_REACHED');
			}
		}New constant QuoteCOM_VIRTUEMART_COUPON_CODE_MAX_USAGE_REACHED="Maximum coupon usage limit reached, please try different code."
On line 1296		if($allow_coupon == 0) {
			$this->couponCode = '';
			return 'Coupon code not valid, please try different code.';
		}Should be		if($allow_coupon == 0) {
			$this->couponCode = '';
            return vmText::_('COM_VIRTUEMART_COUPON_CODE_INVALID');
		}New constant QuoteCOM_VIRTUEMART_COUPON_CODE_INVALID="Coupon code not valid, please try different code"