递归函数出错

Function Traverse(ByVal PN As String, ByVal MakeBuy As String, ByVal Qty As Double, ByVal arr_Comp As Variant, ByVal BOM As Variant)
    j = 0
    For j = LBound(BOM) To UBound(BOM)    'Step through BOM
        If BOM(j, 1) = PN Then  'Parent found in array, is an assembly
            ReDim Preserve arr_Comp(0 To 3, 0 To UBound(arr_Comp, 2) + 1)
            arr_Comp(0, UBound(arr_Comp, 2)) = BOM(j, 2)    'child
            arr_Comp(1, UBound(arr_Comp, 2)) = UCase(BOM(j, 7))    'make/buy
            arr_Comp(2, UBound(arr_Comp, 2)) = BOM(j, 3) * Qty    'exploded qty
            arr_Comp(3, UBound(arr_Comp, 2)) = BOM(j, 1)    'Parent

            Debug.Print BOM(j, 2) & " (" & BOM(j, 7) & ") added to arr_Comp, BOM row " & j

            PN = BOM(j, 2)
            MakeBuy = UCase(BOM(j, 7))
            Qty = BOM(j, 3) * Qty
            If MakeBuy = "E" Then    'Keep progressing through BOM
                Call Traverse(PN, MakeBuy, Qty, arr_Comp(), BOM())
            End If
        End If
    Next j

End Function