Well I haven't tried this pack yet but with the cardboard one it would load at all D: I could find it in the resources area but when I went to add it nothing happened. But I asked around on the UDN and got a fairly relative response that it may be my version of UDK. I am not sure what version this supports but apparently the new beta one I am in still has some problems and supports very little file extensions from before :/ hopefully that will get fixed soon cause all your stuff looks amazing WOOT!
Hehe yea I know xD but the beta does have some extremely cool refinements what I will probably do is block out and set up most of the stuff in the beta version since work flow has increased then take all that and use it in the stable release to add my finishing touches
"What programs accept this file format? Sorry if i ask too much."
Dear friend, if you want to learn to use this texture in a 3D program - the first step is indeed doing research. But please research this for yourself. Don't ask questions you can google for yourself. If you don't invest time and energy in something you want to achieve - you won't make it. So don't ask others to invest energy in something YOU should be investing energy in.