Cannot serialize member System.ComponentModel.Component.Site of type System.ComponentModel.ISite because it is an interface.

when i use this code in web service for database connection
 <WebMethod()> _     Public Function openConnection() As OleDbConnection         Dim con As OleDbConnection         con = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Server.MapPath("App_Data\CRM.mdb"))         If (con.State = ConnectionState.Open) Then             If (con.State = ConnectionState.Open) Then                 con.Close()             End If         End If         con.Open() ...