Enrique:
From the GDL Reference Guide:
REQUEST ("Zone_relations", "", category_name, code, name, number [ ,category_name2, code2, name2, number2])
Returns in the given variables the zone category name and code and the name and number of the zone where the library part containing this
request is located. For doors and windows, there can be a maximum of two zones. The return value of the request is the number of successfully
retrieved values (0 if the library part is not inside any zone).
So this could be from a library part that is not inside a zone. You could try hiding layers until you discover which library part is showing this text, then seeing if there is a parameter for turning the text off.
David