ComboBox enlazados a tablas Access

[jebado]

Tengo esto pero me da error: Referencia a objeto no establecida como instancia de un objeto. ¿Qué hago mal? :b:

Dim strconexion As String
Dim objconexion As OleDbConnection
Dim objcomando As OleDbDataAdapter
Dim objds As New DataSet
strconexion = "Provider=Microsoft.Jet.OLEDB.4.0;User ID=Admin;Data Source=..\BBDD\bd1.mdb"
Try
conn.Open()
objconexion = New OleDbConnection(strconexion)
objcomando = New OleDbDataAdapter("select * from Tabla1", strconexion)
objcomando.Fill(objds, "NomCliente")
Dim row
Dim fila As DataRow
For Each row In objds.Tables("NomCliente").Rows
ComboBox1.Items.Add(row(0))
Next
Catch ex As Exception
MessageBox.Show(ex.Message)
Finally
conn.Close()
'result.Close()
End Try