Resolving /doubleclick/DARTiframe.html 404 errors

We still aren't 100% sure what's causing it - but if you see this on your Google Analytics, it means that somewhere on your site, a service is looking for this file.  Thankfully, it's a quick fix (and straight from Google)

1. Download the iframe solution file (DARTiframe.html).
2. Add the DARTIframe.html file to a /doubleclick folder at the root directory of the web service on your web servers. For example, if your website is www.example.com, put the DARTIframe.html file into www.example.com/doubleclick.
3. Place the iframe solution file on all domains and subdomains where the ad will serve.