The tool and the method in this tutorial work without issues with the latest Insider Build 14271 ESD file, released today.
The tool (cryptokeys needed to decrypt the ESD file) was last updated on January 28, 2016; if you have downloaded the tool after that update you don't have to redownload it. If your tool was downloaded earlier, please remove it (delete the folder) and redownload before using it. The older version of the tool might create faulty ISO image or not work at all with Build 14271 ESD file.
Download link in the first post (step 1.3).