It is only using the second field. The first one can be ignored or removed.
It looks like you have it set to ignore blank values. You can update the code where it says: "WA_IGNORE"
and change it to "WA_BLANK" or "WA_NULL"
That is the area where you set what to do when the field is blank.
I'm not sure what you mean by cannot add data? You mean update a field value? Again I'd have to reproduce the problem to diagnose the cause.