try this,
to find that code i had to log into my account, if you go to the button that says your account and the the button that says Your promotions/e vouchers it shows up there.
anyway the code is
Free Delivery on grocery orders over £50 - CRM LP 011209
Im not sure which part of the code you use (maybe this bit LP 01 12 09 ) and it may be unique to my account, I reckon asda have been sneaky and only added it to peoples account so not everyone can use the same one but it is worth a try.
hope that works