Expression Blend 3 launch error

I've made a fresh install of Expression Blend 3 on Windows 7 64-Bit Ultimate and every time I create a brand new Silverlight 3 Application + Website project in Expression Blend 3 then try and run it I get the error:

Could not start "http://localhost:63523/Default.html" due to the following error: System.ComponentModel.Win32Exception:Application not found

Blend is using the Microsoft Expression Development Server and the icon for the server starts and shows in the system tray so I开发者_如何学运维 know it's running. When clicking Show Details on the icon I can see that the physical path is set correctly to the path of the project. The Default.html file exists in the folder that the Expression Development Server is pointing too.

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I have a similar set up as you (x64, Windows 7 Ultimate, Blend 3) and while I haven't had your particular issue with Blend, I have had others (Catastrophic errors being the norm).

Maybe a reinstall will do the trick? Sorry, I know it's trite.

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I found this was caused by the file association for .url filetype was set to Microsoft Browser rather than Internet Explorer/FireFox. I fixed this by going to Control Panel, Default Programs, Associate a file type or protocol with a program, then selecting .url and navigating to the Firefox.exe executable