I am trying to make a skin for the SW1500, but when I try to import the .dds files into RSBinTool, all I get is this error message:

What am I doing wrong? I am saving it as DXT3 Explict Alpha (as I always have). I have even tried loading up saved files from when I was still working on it and they didn't work. I got the same message.
What should I do? I put 4 hours into this skin I am making, and I do not want to have to redo it.
Thanks,
Noel.