I submitted nothing to the landing page and got: Traceback (most recent call las...

I submitted nothing to the landing page and got:

  Traceback (most recent call last):
    File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/webapp/_webapp25.py", line 703, in __call__
      handler.post(*groups)
    File "/base/data/home/apps/s~oldgreader/1.354495002931951805/main.py", line 25, in post
      blob_info = upload_files[0]
  IndexError: list index out of range