The current EpiVis system (https://delphi.cmu.edu/epivis/) does not allow importing files. At least it cannot work using Safari/Chrome/Firefox
However, this one (https://delphi.midas.cs.cmu.edu/epivis/epivis.html)) works.
From @korlaxxalrok
That alternate link at delphi.midas.cs.cmu.edu will go way soon and eventually redirect to delphi.cmu.edu, but it is interesting that it points to a working system.