Visual Basic.NET - Problema de indice en combos anidados

Private Sub LoadComboimpresora()

        cboImpresora.ValueMember = "idimpresora"

        cboImpresora.DisplayMember = "Name"

        cboImpresora.DataSource = ChinookDAL.GellAllimpresora()

        'DataGridView1.DataSource = cboImpresora.DataSource

        If cboImpresora.Items.Count <> 0 Then

            Dim idimpresora As Integer = Convert.ToInt32(cboImpresora.SelectedValue)

            LoadCombotipo(idimpresora)

        Else

            cboTipo.DataSource = Nothing

            cboCodigo.DataSource = Nothing

        End If