If Chrome DevTools is reporting a 404 for a .map file (maybe jquery-1.10.2.min.map, jquery.min.map or jquery-2.0.3.min.map, but can happen with anything) first thing to know is this is only requested when using the DevTools. Your users will not be hitting this 404. Now you can fix this or disable the sourcemap functionality.
Next, it's an easy fix. Head to http://jquery.com/download/ and click the Download the map file link for your version, and you'll want the uncompressed file downloaded as well.