Many Web resources suggest using aspnet_regiis.exe enable ASPNET to access the GAC, but that was not my particular problem.
Instead, we have a legacy Visual Studio 2005 Web Application Project (not to be confused with a "Web Site") with unusual configuration requirements: It has to run in a virtual directory located at the root of the Web site. Something tells me this is redundant.
Anywho, steps to make it work included:
- Publish to the desired folder (C:\inetpub\wwwroot for example).
- Set both the Web site root and the virtual directory root (in IIS) to that folder.
- In VS, on the Web section of the WAP's properties, under Servers, select "Use IIS Web server".
- In the project URL, put "http://localhost/MyVirtualDirectory".