[RESOLVED] Run-time Error 424 "Object needed" is bugging me

[Tobian]

Following Function give Run-time Error 424 Object needed in the line:LookupValue = Application.Caller.Offset(0, -1).Value.
Where do I use a wrong data type?
Formula gives back only "0", nomather if the statement is true or false.

Function LookOneBack() As Long
Dim LookupValue As Variant
Dim rngMatrix As Range
 
        Application.Volatile
        
        LookupValue = Application.Caller.Offset(0, -1).Value
        Set rngMatrix = ThisWorkbook.Worksheets(1).Range("B1:B4")
        
        If rngMatrix.Find(What:=LookupValue, _
                            LookIn:=xlValues, _
                            LookAt:=xlWhole, _
                            MatchCase:=False) Is Nothing Then
            LookOneBack = 0
        Else
            LookOneBack = 2
        End If
        
        Set rngMatrix = Nothing
End Function