Perhaps that particular cue sheet doesn't contain the exactly correct filename (including the filename extension). You can open the cue sheet in e.g. Notepad and examine & edit the contents.
For example, the filename extension may incorrectly be .wav:
FILE "An Album.wav" WAVE => FILE "An Album.flac" WAVE
or it may contain an incorrect and unnecessary path:
FILE "Some folder\Another folder\The name of the file.flac" WAVE => FILE "The name of the file.flac" WAVE
