The indicated field name has been given to the NEXT FIELD statement or to the pf_nxfield() function, but it is not defined in the current form. A common error is to confuse the tag name, which is used in the screen layout and to the left of the equal sign in the ATTRIBUTES section, with the field name, which is the column name used to the right of the equal sign in the ATTRIBUTES section. Use the latter when you refer to fields.