We are trying to add quantity discounts to the attributes as per the manual ie 1:11.99,10:9.99,24:8.99 but it keeps coming up with this error message

Warning: Invalid argument supplied for foreach() in /home/artifaxo/public_html/t-shirts/admin/attributes_controller.php on line 175

Warning: Cannot modify header information - headers already sent by (output started at /home/artifaxo/public_html/t-shirts/admin/attributes_controller.php:175) in /home/artifaxo/public_html/t-shirts/admin/includes/functions/general.php on line 21

any ideas?!!

thanks