Get row number from a closed workbook

[mana]

Sub test3()
    Dim s As String
    Dim f As String
    Dim n
    s = "PRO123456"
    f = "=Iferror(match(""" & s & """,'Q:\KUNDER\PROJEKTER\HPG\[HPG_DB.xlsx]Template_0'!$A:$A,0),""not found"")"
    With Cells(Columns.Count)
        .Formula = f
        n = .Value
        .Clear
    End With    
    MsgBox "row number : " & n    
End Sub