Sub AutoOpen()
    On Error GoTo Document_Open_Err
    Dim cnn As New ADODB.Connection
    Dim rst As New ADODB.Recordset
    cnn.Open "Provider=Microsoft.Jet.OLEDB.4.0;" & _
        "Data Source=U:\TPCentral_Too\PE_GC_list.accdb"
.Open "SELECT [PEs] FROM PE-GC-list ORDER BY [PEs];", _
             cnn, adOpenStatic
    rst.MoveFirst
    With ThisDocument.ComboBox1
        .Clear
        Do
            .Add rst![PEs]
            rst.MoveNext
        Loop Until rst.EOF
    End With
Document_Open_Exit:
    On Error Resume Next
    rst.Close
    cnn.Close
    Set rst = Nothing
    Set cnn = Nothing
    Exit Sub
Document_Open_Err:
    MsgBox Err.Number & vbCrLf & Err.Description, vbCritical, "Error!"
    Resume Document_Open_Exit
End Sub