Help ----- PyAutoFEP: running "python analyze_results.py ..." gives internal error

[Samuel-gwb]

I successfully progressed into the last analyze step with pack.sh running and getting tutorial.tgz, using default example and some bug-fixing modifications. However, when running the analyze script with following:
$ python analyze_results.py --input tutorial.tgz --units kcal --output_uncompress_directory tutorial_out --center_molecule=FXR_12

Errors appeared as following, with little additional information, which is quite confusing:
###########################################################################
=================== STACK INFO ===================
File "/home/gwb/PyAutoFEP/docs/tutorial01/tutorial/analyze_results.py", line 1345, in
arguments = process_user_input.read_options(Parser, unpack_section='analyze_results')

File "/home/gwb/PyAutoFEP/docs/tutorial01/tutorial/process_user_input.py", line 99, in read_options
os_util.local_print('Failed to read internal data file. Cannot continue. Check your install, this should not '

File "/home/gwb/PyAutoFEP/docs/tutorial01/tutorial/os_util.py", line 313, in local_print
stack_info = '\n'.join(traceback.format_stack())

=================== STACK INFO ===================
[ERROR] Failed to read internal data file. Cannot continue. Check your install, this should not happen
###########################################################################

Please help to find the problem, or indicate how to got detailed information about the error.
Thanks

Samuel