I don't get any errors if I put the related field in a portal. This seems silly to me because I'm only displaying one record, but maybe this is the way that fx.php was designed. Maybe someone else can try these 2 scenarios and tell me if they get the same thing?
I'm new to fx.php but I did get it to start working after much frustration. The first few layouts that I chose in my tests weren't working (FX: ExecuteQuery XML errors and others within the returned array). After I found a layout that worked I realized that it would only return an array without errors if I didn't have a related field on the layout. Does anyone know why?