Why is SkyBox Line showing up during play

i added a sky picture of top, bottom,right,left…and the part where the joined up is showing up a line similar to a camera line which is showing up during play.which is irritating and doesnt look nice

So whats the problem here,is there anyway to solve it??

O i solve it le ,For those who have same problem come this link:

http://unity3d.com/support/documentation/Manual/HOWTO-UseSkybox.html

For each texture you need to change the wrap mode from Repeat to Clamp. If you don’t do this colors on the edges will not match up: