Doesn't work: "mat4 is undefined" (FF) / "Cannot read property 'perspective' of undefined" (Chromium)

[zvyn]

After installing shader-school using npm (see below) I get errors in Firefox and Chromium:
Firefox (version 38.0.5) tells me that "mat4 is undifined" while Chromium (version 43.0.2357.125) "Cannot read property 'perspective' of undefined".
The errors appear in a red rectangle on the right bottom as soon as one of the lessons is loaded (e.g. http://localhost:12492/intro-0).
I only see a black screen and the introduction (as soon as I click the button in the top left corner) plus a folder and a home button. Solving an exercise and clicking verify does not work (I'm pretty confident I solved the first one right).
The output after a request using Firefox:

200    2ms       282B  /
200 3651ms     8.18MB  /index.js ➞ /home/milan/Code/shader-school/node_modules/shader-school/node_modules/browserify ./index.js -d -t /home/milan/Code/shader-school/node_modules/shader-school/node_modules/brfs/index.js -t [ /home/milan/Code/shader-school/node_modules/shader-school/node_modules/envify/index.js --dirname intro-0 --file_hello_glsl /home/milan/Code/shader-school/00-intro-0/hello.glsl ] -t /home/milan/Code/shader-school/node_modules/shader-school/node_modules/glslify-live/transform.js -t /home/milan/Code/shader-school/node_modules/shader-school/node_modules/glslify/index.js

I istalled shader-school using the following command sequence: cd */Code/; npm install -g shader-school --prefix shader-school; mv shader-school/lib/ shader-school/; ln -s shader-school/node_modules/shader-school/index.js .local/bin/

[nkint]

me too. any news on that?

[nkint]

I have reinstalled everything and now it works ok