SHOPPER GROUP PROBLEM

[burtonent]

Novice user of Joomla and Virtuemart. 

I'm using VM 2.0.8 with a Joomla 2.5 template. 

The main menu link is set up to show the product categories and it works, but when you click on one of the categories, you get the following error;

Notice: Trying to get property of non-object in /home/content/b/u/r/burtonent/html/administrator/components/com_virtuemart/models/user.php on line 170

I have the default shopper group set up and the id is 2.  Line 170 in the user.php file reads as follows;

$this->_data->shopper_groups = $this->_defaultShopperGroup->virtuemart_shoppergroup_id ;

Not sure what to do, any help would be appreciated. 

I went into the database and changed the default shopper group id from 2 to 0 and noticed the vendor id was set to 1 so I changed it to my vendor id 2.  The product shows now, but I'm still getting the error and also getting "No standard shopper group set.