Error: Unknown column 'p2c.category_id' in 'where clause'<br

I recently upgraded a client and am receiving the following error when I attempt to click on the Categories option in the Dashboard.

2014-09-22 4:41:05 - PHP Notice: Error: Unknown column 'p2c.category_id' in 'where clause'<br />Error No: 1054<br />SELECT COUNT(DISTINCT p.product_id) AS total FROM oc1_product p LEFT JOIN oc1_product_description pd ON (p.product_id = pd.product_id) WHERE pd.language_id = '1' AND p2c.category_id = '2' AND p.status = '1' in /home/www/clientsite.url/system/database/mysql.php on line 50

I have searched for a solution but have had no luck.
Right now my client's site is down - any help is appreciated.
My DBPrefix is ocart_ I don't know that that would make any difference...