How do I fix the message - "The debug request could not be processed by the server due to invalid syntax."?

I'm developing an extension to a web site. I intend to debug using the local IIS instance on my development machine. When I hit F5 I get the message "Unable to start debugging on the web server. The debug request could not be processed by the server due to invalid syntax."

It's a DotNetNuke module, but I do not think that is relevant.

In Project Properties on the Web tab. I have set Start Action to http://volleyballresults2. I have set Use Local IIS Web Server and the URL is set to http://volleyballresults2/desktopmodules/TestModule/. I have set Override Application Root to http://volleyballresults2.

I have a hosts file entry that maps the name volleyballresults2 to the address 127.0.0.1. If I use IE to navigate to http://volleyballresults2 the site comes up correctly.

If I use Debug | Attach to Process, I can set breakpoints and step through code.

When I hit F5 to start the site I get the error message mentioned above. It's probably relevant that if I hit Ctrl-F5 IE launches; but shows in the address bar http://volleyballresults2/desktopmod开发者_开发知识库ules/TestModule/http://volleyballresults2. This is an invalid URL made up from my two settings. This invalid URL results in a 404 error from IIS. I do not know if this is related to the syntax error referred to.

Environment - Win7 64bit, IIS 7.5, Visual Studio 2008, DotNetNuke 5.6.2

Double check that your main page doesn't have any modules attached to it that reference Content Panes that don't exist in the current skin. I sometimes get this error when I update a skin and remove a content pane that a module was using.

The only way to fix it is to put the content pane back in the skin, then remove the module, then change the skin back OR remove the module reference from the TabModules table.

Discovered it. This is caused, at least in my case, when the web application being launched has debug='false' in its Web.config.