can't run ExcuteReader...

I trying to fconnect my form to microsoft access table and i"m getting the same error all the time:

"An unhandled exception of type 'System.Data.OleDb.OleDbException' occurred in system.data.dll"

the code is:

Private Sub Label1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label1.Click
Dim name As String
Dim sql As String
Dim cn As New OleDb.OleDbConnection()
Dim dr As OleDb.OleDbDataReader

cn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= C:\Documents and Settings\éðéá\My Documents\àìáåí úîåðåú.mdb"
cn.Open()

sql = "select * from mainform"

Dim cmd As New OleDb.OleDbCommand()
cmd.Connection = cn
cmd.CommandText = sql

dr = cmd.ExecuteReader()

While dr.Read()
Debug.Write(dr("picture"))
End While

dr.Close()
cn.Close()

End Sub

and i get the error when he get's to the executereader line.

what should i do?