What error is displayed ?
It says "Install failed - Not a game, game update, DLC, demo or version title" that's for WUP Installer GX2
NUSspli says "File title.tmd invalid"
I'm using Aroma
You need to install sig patches, instructions are displayed when you download the game
But I did, or so my downloaded NUSspli games wouldn't work
I figured out that it was a problem with my old sd card, now it works fine with the new one