Need help with Normal maps

I am trying to make a normal mapped cube but whenever I play my game it doesn’t show. Can someone provide me with a good, indepth tut or see if there is anything wrong with this one:

For normal maps, mini tut:

Firstly, you need this script:

1. Select your object that you want to normal map, go to the shader buttons, and add a new material. 

2. Add two new textures in the material buttons.

3. In the texture buttons, load your detail texture, and your normal map texture in that order. To make normal maps using the GIMP, download the GIMP normal map plugin:

4. Back in the material buttons, select your detail texture and set it up as follows: UV map input, and map to "Col". 

5. Select your normal map texture in your material buttons again, and set it up as follows: Tangent map input, and map to "Nor"

6. Add an empty, this'll be your script holder. To this empty, add an always sensor (single pulse, neither pulse button should be depressed), and connect it to a python controller.

7. Now split your screen and change the new viewport to "Text Editor"

8. Right click in the text editor window, and select "Open"

9. Browse and find the "" script.

10. On your python controller, write in "" in the space provided.

11. In the script, it'll say:
ShaderObjects = [ objlist['OBCube']]
make sure "Cube" is the name of what ever object you're normal mapping. Be shure to keep the prefix "OB"

12. Press P and watch the magic!

13. If the script doesn't appear to do anything, adjust the "AmbF" value slightly. I usually use 1.5

These instructions should work. When I wrote it, I did it step by step as I was writing it. If you’ve rechecked everything you’ve done against my mini tut, then PM me the .blend and I’ll take a look.

okay thanks.