I was only able to recreate your problem by renaming my text field to "customer " (that’s a space that you can not see in the Project Browser. Rename your “customer” text field again.
By the way, those fields for card and pin look like text fields which will give you a problem when you try to get the intValue of them. Just use text and the runPrepUpdate should take care of the rest.
Hmm, but if you used a custom property it will work just fine. OK, ignore me.