Dear Juan, Sorry for the bug, it should be fixed now. The problem with the REPLACEMENT might be due to two reasons: a) you should use Python 3 beacuse of simpler unicode support, b) there is something in your latex files, that I didn't expect writing my parser. I such case, please do send me your file (if it is possible) and I'll try to fix the parser.
Argparse is/was an external module, but is going to be in the Python Standard Library from Python 3.2 on.
Cheers, Asia