I need help please!! Anyone familiar with Marketpress and Marketplace Front end

Ok, I am starting to get closer using marketplace Frontend plugin to create an etsy like site but I am getting an error. I am following the tutorial that Marketplace Frontend put out. I am close to the end. When I go to my site/register store I get the following error:

Warning: unserialize() expects parameter 1 to be string, array given in /home/terry/public_html/wp-content/themes/gridmarket/header.php on line 77

Can anyone help that is familiar with this?