help to block enemy with wall

I place a FirstPerson and tag it as Player and I place a MX soldier and tag it as enemy I have a script where the enemy follows and attacks player . Now I place a wall in between them and use the following colliders:
1652023--103129--upload_2014-6-4_11-8-13.png 1652023--103130--upload_2014-6-4_11-8-39.png
this for the cubeWall barrier This for the Enemy Max soldier
I have tried I think every conceivable combination therein without success the enemy just walks thru the wall
What else do I need?

1652023--103129--upload_2014-6-4_11-8-13.png

Your player and enemys should have a ridgidbody attached, with gravity checked and kinematic unchecked.
The walls not need to have a ridgidbody. Walls normally static objects. Ridgidbodys are for moving objects.
The walls only need a (box)collider attached.

Your box collider has a z-size of zero. That means it’s a 2D object with no volume so you can’t ever collide into it.

EDIT: Also, what is a negative x-size mean with colliders? O.o