Fatal error: Cannot use object of type stdClass as array in …

Store URL (if not provided we can’t help much):
 weprintnumbers.com
WordPress version: 4.2.2

WP eCommerce version: 3.9.3

Gold Cart version: None

Theme: WordPress 2013 child
I did this: Added <?php echo wpsc_shopping_cart(); ?> to the
/twentythirteen-child/wpsc-single_product.php page.
Upon adding products to the cart I get this error
Fatal error: Cannot use object of type stdClass as array in /home/linuxcpanel/public_html/weprintnumbers.com/wp-content/plugins/wp-e-commerce/wpsc-includes/cart-item.class.php on line 154
I have tested over 2 different servers, php 5.4 and 5.5, and reverted back to default code and am still getting the error. I have updated the base theme to correct the “countries” error that is known.
I have come across documentation suggesting the code in cart-item.class.php on line 154 may need to be rewritten but am unsure of how exactly to do that.
I expected WPeCommerce to do this: Continue to add products to the cart and display them in the cart widget.
Instead it did this: Added 2-10 products before producing the error above and locking up the site.

Thank you for your help. I’ve been trying to use WPeCommerce for years but have always gotten errors, I would really like it to happen this time. I would purchase a gold cart as well but I have never been able to get a functioning site. Please help me so I can confidently buy your product.

https://ww.wp.xz.cn/plugins/wp-e-commerce/