Does anyone know what I could try to make this contribution work with 1.3.5? Installed as is, on the shopping cart page it gives the following error:

Warning: Division by zero in /home/baby/public_html/new/includes/modules/custom/cart_upsell.php on line 77
1065 Query was empty
in:
[]
I know something is obviously wrong in that file and it's not getting the info correctly from the database, but I'm just not sure what I need to change...does anyone have any suggestions?

Thanks!