Can't execute query

SELECT I.product_id , I.product_name , I.product_promo , 
        (SELECT G.gal_img FROM product_item_gallery as G WHERE G.product_id = I.product_id AND G.dspflg = '1' AND G.gal_cover = '1' )  as cover , 
        (SELECT GF.gal_img  FROM product_item_gallery as GF WHERE  GF.product_id = I.product_id AND GF.dspflg = '1' ORDER BY GF.gal_order LIMIT 1 )  as cover_f
        FROM product_item as I  WHERE I.product_display = '1' AND I.dspflg = '1'  AND  I.product_group LIKE '%:7:%'  ORDER BY I.product_order ASC , I.product_name ASC  LIMIT -36  , 36

MySQL Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '-36 , 36' at line 4

This script cannot continue, terminating.