Skybox square border

I checked the tutorials but I can't find anything about this problem. When i tested the skybox in my map, it was fine except that it shows a square border where the two faces come together.
Like this:

http://tinypic.com/1t60cj

Any help appreciated.

that happens with me too, but i've not got 'round to looking for an explaination yet. :/

The default Wasteland skybox does that with some videocards/drivers.
Try using a different one, like sky_day02_01 (which is quite similar).

This is assuming you've done it right: put the toolsskybox texture on
your brushes, and the sky name in the Map/Map Properties / Skybox
property.

yep, I got that problem to I can fix it by turning up the graphics a
notch or like said above us a diff. skybox. btw its a GeForce FX 5700
AGP 8/128 MB

just open up console and type buildcubemaps and that will fix it, just make sure you have a env_cubemap in your map.

http://www.hl2world.com/wiki/index.php/Sky_List

all the skys for HL2

Rof got it right. No self-respecting mapper should use the wasteland sky texture.

And DjBourgeoisie, the problem has absolutely nothing to do with
cubemaps. It's completely irrelevant. You might as well
suggested "why don't you put mustard on your buns?"

Well, changing the skybox fixed it. Thanks Rof.