I just saw this post, if you have downloaded that example data and now are trying to upload it according to the screenshot above, you have selected the wrong ID type.
KEGG ortholog is for IDs of the form “KO#####”. For Seq2Fun ortholog IDs (of the form “s2f_##########”) you must select ‘Seq2Fun Ortholog ID’ for the ID type.
If you want to use the example data without going through the upload process, you can simply select the data radio button and click ‘Submit’.