ShopperPress error while click on a product in the homepage

Hi All,
I am using shopperpress for my amazon affiliate store.
But I am getting an error when click on any products in the homapge. It happens only the first time I click there. Here is the error :
Fatal error: Uncaught exception 'Exception' with message '<h1>There was an error but don't panic..</h1><p>Your AccessKey Id is not registered for Product Advertising API. Please use the AccessKey Id obtained after registering at https://affiliate-program.amazon.com/gp/flex/advertising/api/sign-in.html.</p>' in /home/user/public_html/wp-content/themes/shopperpress/PPT/class/class_amazon.php:435 Stack trace: #0 /home/user/public_html/wp-content/themes/shopperpress/PPT/class/class_amazon.php(555): AmazonProductAPI->verifyXmlResponse(Object(SimpleXMLElement)) #1 /home/user/public_html/wp-content/themes/shopperpress/template_shopperpress/_single.php(102): AmazonProductAPI->getItemByAsin('B009NHU556', 'com') #2 /home/user/public_html/wp-content/themes/shopperpress/single.php(246): include('/home/user/...') #3 /home/bringme4/public_html/wp-includes/template-loader.php(47): include('/home/user/...') #4 /home/user/public_html/wp-blog-header.php(16): require_once('/home/bringme4/...') #5 /home/user/p in /home/user/public_html/wp-content/themes/shopperpress/PPT/class/class_amazon.php on line 435

Anyone here to help me solving the issue ??

Thanks