I don’t know much, but I know the file it’s looking there for is the actual emulator. That’s where it’s located. You also have to find and download a file on the net called gba_bios.bin and put it in that same folder. But if that were the only problem, it would tell you. I’m guessing your compile failed somewhere along the way.
Sorry, but I’m completely new at this stuff and can’t help you much more than that.