Essayez de changer le code :
<?php
if(!isset($this->element->hikashop_params['show_price'])) $this->element->hikashop_params['show_cart_price'] = '-1';
echo JHTML::_('select.radiolist', $arr, $this->control.'[show_price]', 'onchange="switchDisplay(this.value,\'show_taxed_price_line\',\'1\');switchDisplay(this.value,\'show_original_price_line\',\'1\');switchDisplay(this.value,\'show_discount_line\',\'1\');switchDisplay(this.value,\'price_display_type_line\',\'1\');"', 'value', 'text', @$this->element->hikashop_params['show_price']);
if(!@$this->element->hikashop_params['show_price']) $this->js .='switchDisplay(0,\'show_taxed_price_line\',\'1\');switchDisplay(\'0\',\'price_display_type_line\',\'1\');switchDisplay(\'0\',\'show_original_price_line\',\'1\');switchDisplay(\'0\',\'show_discount_line\',\'1\');';
?>
en:
<?php
if(!isset($this->element->hikashop_params['show_cart_price'])) $this->element->hikashop_params['show_cart_price'] = '-1';
echo JHTML::_('select.radiolist', $arr, $this->control.'[show_cart_price]', 'onchange="switchDisplay(this.value,\'show_taxed_price_line\',\'1\');switchDisplay(this.value,\'show_original_price_line\',\'1\');switchDisplay(this.value,\'show_discount_line\',\'1\');switchDisplay(this.value,\'price_display_type_line\',\'1\');"', 'value', 'text', @$this->element->hikashop_params['show_cart_price']);
if(!@$this->element->hikashop_params['show_cart_price']) $this->js .='switchDisplay(0,\'show_taxed_price_line\',\'1\');switchDisplay(\'0\',\'price_display_type_line\',\'1\');switchDisplay(\'0\',\'show_original_price_line\',\'1\');switchDisplay(\'0\',\'show_discount_line\',\'1\');';
?>
dans le fichier "form" de la vue "modules" pour le template de votre back end puis de sauvegarderles options du module à nouveau.