unable to insert dropdown data into database

Actually
in form people select their card from dropdown e.g. visa, master card etc.
after this i was unable to store data into database but now finally i store data in database but still unable to validate cradit card or debit card validation.
i use following validation in my page but still not able to validate the values.
http://tutsnare.com/credit-card-validati...deigniter/

hope it'll help you.
Thanks in advance
Nady