If you mean DEcompressing it is talking about winrar which is kind of like winzip to put it bluntly what it does is it takes one big file and makes lots of little compressed ones. What you need to do is download winrar,(i think you can get it from dccopyworld) then install and run winrar and decompress the files and it will give you a .cdi file or a .bin with a .cue file.

Hope that helped