The problem is triangulation. All user level graphics cards usually handle tris and not quads or ngons.
I suspect that you have mapped that whole front to a rectangular bit of texture, right?

So let's say the 2nd one is how your polygon actually looks (shapewise) and the first one is how you have it on the UV, then you would expect it to look like the 2nd one, but it looks like the 3rd one. I did not get this for quite some time, but if you look at an image like that you can see where the diagonal goes and how it affects the texture.
There are 3 things you can do afaik.
1) Have the shape on the UV correspond closer to that of the actual polygon.When you UV Unwrap it select the 2 front polygons and then click planar and then reset. This makes sure that the shape is retained.
2) Add more polygons.
3) Sometimes it helps to flip the edge in the middle of the quad, tho it escapes me where you can do that in Max atm. I guess it should be possible somewhere in the UV Unwrap window or on rightclick in Edge mode.