Exporting 3D model from Maya, back into LoL

So, I've imported the Pax Sivir .skn file to Maya and made some basic adjustments. Now I'm ready to export it and install it in game using SIU. I overwrote the original sivir_pax.skn file (or at least I thought I did) and selected it among my files to add my custom skin. I ran a custom game to test the new model, but I didn't make it past the loading screen because the client crashed. It told me that the file 'Sivir' was missing. I don't know how to fix this. I'd appreciate any help!