Error-- the web server is configured to not list the contents of this directory (win7, IIS7)

I created a simple/basic/test wcf service library (which appears to work in test mode).  Then I created a simple/basic asp.net (empty) web application test client (for the wcf service library) in Visual Studio 2012.  I was following a walkthrough on msdn (except they used a winform for the test client).  My web app did not contain a Default.aspx page, so I added a webform.aspx file (named WebForm1.aspx).  I also enabled directory browsing in the IIS7 manager (I did not restart my workstation -- win7) though - yet).  There is no web.config in the wcf service library, and I did not make any changes to the web.config in my web app.  The screen capture below shows the error I receive when I try to run the web app.  Do I need to do anything in web.config of my web app?  Or do web apps not work with wcf service libraries (as opposed to a wcf service application -- which does appear to contain a web.config file)
Thanks in advance ...