Error message

• Notice: Undefined index: und in _carpediem_cart_contents() (line 88 of /home/biodobrote/public_html/narocila/sites/all/modules/custom/carpediem_cart/carpediem_cart.module).
• Warning: Invalid argument supplied for foreach() in _carpediem_cart_contents() (line 88 of /home/biodobrote/public_html/narocila/sites/all/modules/custom/carpediem_cart/carpediem_cart.module).