Error in Importing data from excel file to database using c#.net

Here is my code...

constr = string.Format(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=""Excel 12.0 Xml;HDR=YES;""", FilePath);

    Econ = new OleDbConnection(constr); ExcelConn(FilePath);
    Econ.Open();

    Query = string.Format("Select [Emp ID],[Emp Name],[Log Date],[LogTime],[Type] FROM [{0}]", "One Month Report$");
    OleDbCommand Ecom = new OleDbCommand(Query, Econ);

    DataSet ds = new DataSet();
    OleDbDataAdapter oda = new OleDbDataAdapter(Query, Econ);
    Econ.Close();
    oda.Fill(ds);
    DataTable Exceldt = ds.Tables[0];

    //creating object of SqlBulkCopy    
    SqlBulkCopy objbulk = new SqlBulkCopy(conn);
    //assigning Destination table name    
    objbulk.DestinationTableName = " Attendancetable";
    //Mapping Table column
    objbulk.ColumnMappings.Add("Emp ID", "Emp ID");
    objbulk.ColumnMappings.Add("Emp Name", "Emp Name");
    objbulk.ColumnMappings.Add("Log Date", "Log Date");
    objbulk.ColumnMappings.Add("LogTime", "LogTime");
    objbulk.ColumnMappings.Add("Type", "Type");
    //inserting Datatable Records to DataBase    
    conn.Open();
    objbulk.WriteToServer(Exceldt);
    conn.Close();

Using this code am getting "External table is not in expected formt" this error. opened excel sheet uploading is successfull but in closed excel sheet file uploading process showing this error. please anyone help me out.