Along with theme's version 2.5.2, the widget called The Retailer Connect was updated. A few more social media options were added and the widget was renamed to Social Media Profiles. The fact that plugin was renamed results into an error for those who already have it assigned to one of the widget areas. It would look something like:
To get past this issue, you need to remove the old widget from the widget area and use the new one instead, the one called "Social Media Profiles".