MVC2: "File not found" after view is painted

This is wierd.

First, I'm building a site based on someone else's framework (Piers Lawson: Creating a RESTful Web Service using MVC ), so I'm not entirely sure what's going on under the covers. But when I run it in VS 2010 by pressing F5, it brings up the Home page, and THEN traps an error in Application_Error. The error is "File does not exist" exception. But I have no idea what file it's looking for. Where does flow control go after the View is finished di开发者_高级运维splaying? How can I break to find out what it's looking for?

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The error could be any other file reference in the page (Css, javascript or images).

Let VS to continue without halting and use FireBug to spot the file that is missing.