Connection breaks with "loadResourceForFrontend failed"

[AugustSaintFreytag]

When launching the app code with ./node_modules/.bin/electron . --debug-brk=5858, it takes a while for Chrome at http://127.0.0.1:8080/?debug=5858to load the sources; Then it halts at the first line after hitting pause to refresh the frozen view. Once it hits the line require("electron") in init.js, it crashes with the following console output (in Chrome):

Network.loadResourceForFrontend failed.
Error: ENOENT: no such file or directory, open '/Users/Freytag/Sites/cornerstone/node_modules/electron-compile/lib/${newMapPath}`);'

Using node 6.9.5, npm 3.10.10 with electron-inspector 0.1.4 alongside electron-prebuilt 1.4.13, electron-prebuilt-compile 1.6.2, electron-rebuild 1.2.1.