Is there actually a controller called look with an action called at?
This isn't really a bug, but is to do with what the browser is reading the URL as meaning. IE is thinking that you are requesting a windows file from a local windows network, Firefox is trying to read the address as a proper http url. If you're developing for the web you should always use unix style / slashes, not windows style \ slashes.
Lets have a look at your routes.rb. And the source for your look controller.
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