title: Error from OdbcDataAdapter.Fill
body: <p>I sometimes get two different of error when executing  OdbcDataAdapter.Fill(DataTable). 
  Here is the code example:</p>
  
  <pre><code>string odbc = "select item, upcno from table";
  OdbcCommand cmd = new OdbcCommand(odbc, fconn);
  OdbcDataAdapter oda = new OdbcDataAdapter(cmd);
  oda.Fill(dt);
  </code></pre>
  
  <ol>
  <li><p>System.NullReferenceException: Object reference not set to an instance of an object.</p></li>
  <li><p>System.InvalidOperationException: No data exists for the row/column.</p></li>
  </ol>
  
  <p>Does anyone have clue to resolve this problem?</p>