I`ve downloaded a skin, and i put it in data/skins.
It isnt a dds file. But the skin doesnt work.
Whats the problem?

I use Demo.

Thanks.

EDIT:

Ur skinfolder looks pretty empty, all the standard skin are not there. Here u can download them http://www.lfsforum.net/showthread.php?t=19570. Look here too find out how to use a skin: http://www.lfsforum.net/showthread.php?t=11182

Its working now, hehe.