Can't load IRender nXt to SketchUp 8

Hello,

I've downloaded a trial version of IRender nXt, but I just can't make it show on Sketch Up 8. I have Windows 7.

I wen't trough all the steps I could find:

Looking on the Plugins Tab;

Checking if the toolbar is available, on the View tab;

Clicking Window> Preferences> Extensions;

Loading it using the Ruby Console;

By using the Ruby Console, I could load "IRender nXt / nXtRender" to the Extensions (Window> Preferences...). But I have to do it every time that I open SketchUp and I can't make it show up there. Not on the Plugins or on the Toolbars...

Can someone please help me? I am desperate. I've been trying to install any decent rendering plugin for sketchup since Saturday and NOTHING works. 

I need something URGENTLY!

Thanks!!!