Problems w/ multiple materials + Render Game

Hello there…

I have a guitar model to which I added a bunch of different materials in order to assign different colors for each part of the mesh. I did it the way I would usually do in Blender Render engine.

Now I’m trying to render it through blender game and this materials behave randomly as I press P.

Like this: I press P once, the material look a certain way; ESC; I press P again, the materials look different! as if they had been deleted!; press P once more, voilà, there’s no problem… :confused:

(Sometimes I get lucky and the material don’t change that often… so I have to press P key repeatedly to see the changes)

I tried removing all materials to start from scratch but then the guitar went all white!

guitarra3.blend (600 KB)

Please help me solve this issue!!!

not seeing this problem. repeated pressing of the p key makes no changes to the materials.

edit:
oh wait theres some stuff going on at the back of the model.

oh Ngons, theres a surprise. cut your mesh into quads.

Should I do this with the Knife or there’s a better way to do it?

edit:
ok… I’ve already changed the ngons into quads but no changes with the render problem…

the render look like the following images (and the one that is right is the last one)