I took a screenshot of the error and placed the order without the gift card. I''ll just call Apple in a few days...
I chatted with a rep online and she just told me that they are aware of the error and to try again later.
I remember seeing last year that they had something along the lines of "if you did not receive a gift card with your macbook but were eligible, fill out a claim" i'll chat with them tomorrow, just put my air order in