Объясните, кто знает

На уровне модуля объявил

Public Type complex
x As Single
y As Single
End Type

Public z As complex

и затем передаю z в процедуру. В ответ получаю следующее:


Only public user defined types defined in public object modules can be used as parameters or return types for
public procedures of class modules or as fields of public user defined types


This error has the following cause and solution:

You attempted to use a public user defined type as a parameter or return type for a public procedure of a class
module, or as a field of a public user defined type. Only public user defined types that are defined in a public
object module can be used in this manner.

Что хочет от меня VB не врубаюсь.