Problem with FldRef.RELATION

I have a problem with FieldRef.RELATION. I want to know, if a Field has a relation to another table. Therefore I use the FldRef.RELATION to find out the Table No. If the field has a relation, all works fine. But if there is no relation, the fin.exe crashes. I use 3.70 incl. HF12 (newest Runtime). What’s wrong? RecRef.GETTABLE(MyTable); FldRef := RecRef.FIELD("Field No."); IF FldRef.RELATION <> 0 THEN BEGIN // <-- fin.exe crashes here if RELATION is 0 [...] END;