Executereader requires an open and available connection

[Manesh Pawar]

Hello,
I m getting an error "System.InvalidOperationException - Executereader requires an open and available connection"
I have Open an Connection, but still it throughs an Error. But it occurs Sometimes..

Following is the code,

 
 
 if (con == null)
     con = new OleDbConnection("" + StrConnection);
 
 if (con.State == ConnectionState.Closed)
     con.Open();
   OleDbCommand cmd = new OleDbCommand("Select (Max(BOMId)+1) as BOMNo from BOM ", con);
  OleDbDataReader dr = cmd.ExecuteReader(); // error occurs at this Line  
     while (dr.Read())
       {
          ----
 

What Could be the problem??