Just a note:
Firefox for Mac has a common problem with processing .ashx files directly (i.e. directly linking to them).
This is usually something that can be seen with PDF files, as it will try to open the .ashx og file without checking the location of the content.
Be aware of problems with Firefox on Mac, as PDF files do not work there.
To do this, you need to configure some things according to:
http://sdn.sitecore.net/scrapbook/media%20files%20downloaded%20with%20ashx%20extension.aspx
if you cannot access, this basically tells you to go to web.config, find this:
<mediaType name="PDF file" extensions="pdf">
and change
<forceDownload>false</forceDownload>
to
<forceDownload>true</forceDownload>
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