Using dotTrace with 2005 Web Application

I am trying to run dotTrace 3.1 against a 2005 project using the ASP.NET Development Server option.

The settings I'm using are:

ASP.NET Development Server - checked
Path to web-server root: c:\projects\fooProject
Virtual path on server: /barApplication
Port: 81 (automatically detected)

      

        
        
        
      

    

This will start, but the webpage won't show up, so I installed:

Open start page in browser - checked
Page Url: http://localhost:81/barApplication/login.aspx

      

        
        
        
      

    

This throws an exception at runtime:

The parameter 'C: / Projects / fooProject \' is not valid. Parameter name: C: / Projects / fooProject \

I ran webdev.webserver from the command line and everything works fine.

What am I doing wrong?