Fatal error message after updating new version


After updating/activating new version of MarketPress the page is showing this error
Fatal error: Call to undefined function mp_product_class() in /home/moretiqu/public_html/wp-content/plugins/marketpress-grid/marketpress-grid-shortcode.php on line 123

the line (123) has this code
$content .= '<div '.mp_product_class(false, $class, $post->ID).'>';

How do I correct this....do I have to deactivate the earlier uploaded "MarketPress Grid" plugin? Or do I have to add something to the code so that it works?