Marcie lets folk know how to get around the 'Unable to Start Debugging' error:

http://weblogs.asp.net/datagridgirl/archive/2004/03/04/83827.aspx

On a related note, every once & a while, I hear about the requests coming in from PSS (Product Support Services). Today, we were discussing a similar error, but one caused when you set a "Forbidden" file type (like web.config) as the start page. Don't do that. :P

TTFN - Kent