You will need to open the Splinter Cell Exploit with Evox with a zip program. The way the save comes you can't just use it. You will have to follow this procedure to get it onto the memory card using the Action Replay Software.
Quote from themuffin:
take one of the directories from the uDATA dir and put it in its own uDATA folder (if this confuses u, when this is done, you should have two folders called uDATA each with only one folder inside, but those folders are different, one contains the actual SC save and the other has evox) (i had to do this, don't know if its needed) poke around the other saves that came with your AR, look for a file called datelinfo or such, and put that in both of your udata folders. now this is the MOST I amPORTANT STEP, make sure that when you zip the files (there should be two seperate zips) inside of the zip there is still the uDATA folder, because sometI ames the zip prog will only zip the files inside and ignore the directory they are in, I use power archiever so it might be different in another case, but its never paranoid to double check. copy over to your mem card using the included software(cross your fingers that it doesn't say "invald Xbox save")