I got the same problem with the auto-installer:
Cloning MagicMirror Done!
Installing dependencies ...
npm WARN deprecated minimatch@0.3.0: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
npm WARN prefer global coffee-script@1.10.0 should be installed with -g
npm WARN prefer global colorguard@1.2.0 should be installed with -g
> electron-prebuilt@1.2.4 postinstall /root/MagicMirror/node_modules/electron-prebuilt
> node install.js
module.js:442
throw err;
^
Error: Cannot find module '/root/MagicMirror/node_modules/electron-prebuilt/install.js'
at Function.Module._resolveFilename (module.js:440:15)
at Function.Module._load (module.js:388:25)
at Function.Module.runMain (module.js:575:10)
at startup (node.js:160:18)
at node.js:456:3
[…]
npm ERR! Linux 4.4.13-v7+
npm ERR! argv "/usr/bin/nodejs" "/usr/bin/npm" "install"
npm ERR! node v6.2.1
npm ERR! npm v3.9.3
npm ERR! code ELIFECYCLE
npm ERR! electron-prebuilt@1.2.4 postinstall: `node install.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the electron-prebuilt@1.2.4 postinstall script 'node install.js'.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the electron-prebuilt package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR! node install.js
npm ERR! You can get information on how to open an issue for this project with:
npm ERR! npm bugs electron-prebuilt
npm ERR! Or if that isn't available, you can get their info via:
npm ERR! npm owner ls electron-prebuilt
npm ERR! There is likely additional logging output above.
npm ERR! Please include the following file with any support request:
npm ERR! /root/MagicMirror/npm-debug.log
You can find the npm-debug.log file here : http://s000.tinyupload.com/index.php?file_id=35118371794828376162
I used a Raspberry pi 2 with a fresh install of Raspbian Jessie and I followed the step by step tutorial (https://forum.magicmirror.builders/topic/236/complete-setup-tutorial)