MySQL Forums :: MySQL Query Browser :: Column can not be null

Hey Guys.
I'm trying to write a function that will insert values into table.
The function should get the values from outter asp application, thus the sql i wrote is:
INSERT INTO customer(customer_name,customer_city) VALUES (@customer_name, @customer_city);

But im keeping getting the error "Column "customer_name" can't be empty.
What's wrong?

Thanks ahead