I have tried to make the app quite robust but if the uploading fails, you can try to convert your TextGrids to UTF-16. And check that all tiers have names
This will be a Excel file, with two columns, the first named file and the second with te group for example sp-maria.TextGrid and Spanish in the second column.
How have you annotated your TextGrids? Phonetic transcription? Maybe orthographic? Or you have just labelled whether sounds were consonants or vowels (CV)
To download the graphs you can drag them to your Desktop.