I just got a new desktop computer with Windows 7 Pro as the operating system. I installed Visual Studio 2008 on to this new computer and tried to open a previously existing ASP.
I appreciate your response.
However, this issue turned out to be an IIS7 issue. The error message I described arose out of the distinction made in IIS7 between a "virtual directory" and an "application" (I don't know if such a distinction existed in IIS6). To fix this error, I opened IIS7, right-clicked on the virtual directory folder for this site, and selected "Convert to Application." I then refreshed the browser, and the error went away.
Sigh.