Gator Epp

Thanks in advance to anyone who is able to offer any help with this. So I recently received a New 3DS XL with CFW (Luma). I did not mod the console myself, and I'm very new to all of this, so I apologize for my cluelessness. I have been playing a ROM of Pokémon Blue that is accessible on this 3DS through TWiLight Menu++. I hooked the microSD card from the 3DS up to my computer to access the .sav file with PKHeX, and found it no problem, right next to the .gb file for the game in the roms folder. But when I tried to open the save in PKHeX, I received the error message shown in the title. I have PKHex set to Pokémon Blue [INT], and the .sav file is from me saving in-game multiple times with the menu, not saving the ROM state. As I said, I'm very new to this, so I'm out of ideas as to what could be wrong. Thanks again in advance to anyone who's able to help me out here! Pokemon - Blue Version (USA, Europe) (SGB Enhanced).sav