What you rightly mentioned, what you're getting is a design time error NOT a runtime error. In other words, the code should successfully run without error. The reason for this design time error is that the SqlDataSource control in the SqlDataSource.cs file is wrongly annotated with the following metadata attribute:
[DesignerAttribute("System.Web.UI.Design.WebControl s.SqlDataSourceDesigner, System.Design, Version=22.214.171.124, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")]
If you remove this metadata attribute, the design time error you're getting should go away.
Shahram Khosravi, Ph.D.
Author of Professional ASP.NET 2.0 Server Control and Component Development