Help with a vlookup through entire workbook macro

I'm trying to use a macro that will search the entire workbook. Here is the macro I'm using:

Function VLOOKUPWORKBK(Look_Value As Variant, Tble_Array As Range, Col_num As Integer, Optional Range_look As Boolean)
'Vlookup function that will search all worksheets in the workbook - however, the data table that is being searched must be in the same
'location on every worksheet.
Dim wSheet As Worksheet
Dim vFound
On Error Resume Next
    For Each wSheet In ActiveWorkbook.Worksheets
        With wSheet
            Set Tble_Array = .Range(wSheet.Name & "!" & Tble_Array.Address)
            vFound = Application.WorksheetFunction.VLookup(Look_Value, Tble_Array, Col_num, Range_look)
        End With
        If Not IsEmpty(vFound) Then Exit For
    Next wSheet
    VLOOKUPWORKBK = vFound
End Function

When I call the function I use this: =VLOOKUPWORKBK(A3,$A$3:$A$103, 4, 0) but it just returns a zero everytime.

I have attached the workbook. You will find the function on the "materials list" sheet in cell d3.

Any help would be appreciated!