User defined function returns #Value when argument is Defined Row Name

Hello, newbie on the forum here, not newbie with VBA. But I am stuck with the following (simple example given):

I am getting a #Value error with VBA user defined functions when I pass on defined row names as arguments; For example here is my User defined function:
Option Explicit

Function Multiply(Param1 As Integer, Param2 As Integer) As Integer
Multiply = Param1 * Param2
End Function

When I define Row 1 as Param1, and Row2 as Param2 and enter =Multiply(Param1, Param2) in Row 3, it returns the #value error

Thanks a lot for helping to solve this!

All right, found a solution:
Function Multiply(Param1 As Variant, Param2 As Variant) As Integer
Multiply = Intersect(Application.Caller.EntireColumn, Param1) * Intersect(Application.Caller.EntireColumn, Param2)
End Function