Many times we came across in debugging legacy applications built on ASP and COM. Debugging of legacy applications are error prone and complex.
We have an application built on ASP and C#.Net 1.1. User Interface defined using ASP and the business logic is in C#.Net. C#.Net project build to a COM component using the NAnt Build (http://nant.sourceforge.net/) tool.
For incorporating new requirements we need to debug the C# project. We have faced many issues in debugging C# project hosted as COM component and used by the ASP pages.
For more details, please refer http://www.dotnetfunda.com/articles/article2063-debugging-an-asp-project-with-csharpnet-11-and-com-using-visual-studio-2003.aspx