There is literally no need to try to get that to work when you can use SlickGrid - https://github.com/mleibman/SlickGrid - which is framework agnostic and tested to work well with 1 million rows.
Aside from that, you can fix it and upgrade the code to MooTools 1.4.5 but that's broken in IE11 - really need to wait for 1.5 release (soon!) before getting started.