Comments by Jacobb Michael (Top 1 by date)

Thank you for the Ref:

and
string connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" +
"Data Source=" + filename + ";" +
"Extended Properties=Excel 8.0;";
OleDbConnection objConn = new OleDbConnection(connectionString);

this is the connection string used in that example it is similar to the connection string what i have created.

and still i get "External table is not in the expected format" error.