Okay, I tried again using a new file and it worked. Sorry for wasting your time!
When I click the verify button the GUI, it works. It just won't transcode.
Embarassingly, I can't figure out how to do that. I tried reading the README and the info on XLD's website, but I haven't been able to get it to work.
The progress window doesn't open until the transcode fails, and I get the same error even if I don't use a .cue.
"Error has occured in the decoder" when transcoding from a .CUE