Pitch finding dies on unexpected json inputs about rodan HOT 2 CLOSED

[2012-06-29 23:48:52,310: DEBUG/PoolWorker-2] Running the finding code.
[2012-06-29 23:48:52,311: WARNING/PoolWorker-2] 1. Finding staves.
[2012-06-29 23:48:52,886: WARNING/PoolWorker-2] 2. Finding staff coordinates
[2012-06-29 23:48:52,886: WARNING/PoolWorker-2] 3a. Finding technique is miyao.
[2012-06-29 23:48:52,909: ERROR/MainProcess] Task rodan.jobs.pitch_finding.pitch_find[4d4210b7-4ded-439a-ac04-1cc9f616ce63] raised exception: TypeError("'NoneType' object is not iterable",)
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/celery/execute/trace.py", line 181, in trace_task
    R = retval = fun(*args, **kwargs)
  File "/home/wliu/rodan_source/rodan/jobs/utils.py", line 56, in real_inner    outputs = f(*input_paths, **kwargs)
  File "/home/wliu/rodan_source/rodan/jobs/pitch_finding.py", line 25, in pitch_find
    recognized_glyphs = aomr_obj.run(glyphs, poly_list)
  File "/home/wliu/rodan_source/rodan/jobs/aomr_resources/AomrObject.py", line 111, in run
    self.sglyphs = self.miyao_pitch_finder(page_glyphs)
  File "/home/wliu/rodan_source/rodan/jobs/aomr_resources/AomrObject.py", line 379, in miyao_pitch_finder
    line_or_space, line_num = self._return_line_or_space_no(g, center_of_mass, staff_locations, miyao_line) # line (0) or space (1), no
TypeError: 'NoneType' object is not iterable