Welcome to the forums.
I think usually a question like this can go in the trouble shooting thread here: http://dissidiaforums.com/showthread...roubleshooting
Anyway, you can rename the gmo to the largest edat file name of the DLC you want to use. Then, rename the gim to the second largest edat file name. Then, put all the files of that DLC into your DLC folder. Make sure you change the extensions to .edat as well.
There's also a detailed explanation of how to use gmos and gims here: http://dissidiaforums.com/showthread...POSTING-PART-2!!!)
I hope this helps.