Read [url=http://dynamic4.gamespy.com/%7Emap/mohaa/tutorials/sunlight.php:b70cc]this tutorial[/url:b70cc] about creating skys and adding sunlight to a map. I'd read the other tutorials on there to....
A sky texture is supposed to repeat many times
Hmmm, do you have Spearhead installed? And with which game do you test your map? AA or SH?
I read something bout it on a german forum: They're saying, that this happens, when you try to use a Spearhead Texture for AA. Most of the AA skies are named after the map, for example m1l1. Try one of them. Or a texture called omahaday or something like that.