I have 5 combo boxes that must have the same rowsource

When I try to program this in VBA, the first one works but then after that I
receive the 424 Errror. I can't manually set it because the range changes, so
i have the code set up to get the last cell...

if anyone could help me that would be great....

Private Sub FillOrders(intLa As Integer)

cmbISBN1.RowSource = "Pinder!E2:E" & intLa
cmbISBN2.RowSource = "Pinder!E2:E" & intLa
cmbISBN3.RowSource = "Pinder!E2:E" & intLa
cmbISBN4.RowSource = "Pinder!E2:E" & intLa
cmbISBN5.RowSource = "Pinder!E2:E" & intLa

End Sub