I cant make thok barrier

[Miles Knuckle Power]

(first, I brazilian, sorry if my English is terrible)

I tried to make a Thok barrier, I make all I see in Wiki, but I cant make a correctly thok barrier!
Here one example of map I tryed to make the thok barrier:

http://www.megaupload.com/?d=G8UWIG3E

Who can help me?

 

[Puppyfaic]

Yeah, I can.

You forgot to make sure the thok barrier's floor and ceiling heights are the same. That's all.

 

[Miles Knuckle Power]

Man, you saved my live!
Thanks!