Following the blame history, this appears to be new issue following issue5845.

I'm using Python 3.4b2 64-bit on Windows. I've installed pyreadline 2.0 using Setuptools 2.1. Now, when I start the interactive interpreter, I get this output:

> python
Python 3.4.0b2 (v3.4.0b2:ba32913eb13e, Jan  5 2014, 16:13:26) [MSC v.1600 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
Failed calling sys.__interactivehook__
Traceback (most recent call last):
  File "c:\python\lib\site.py", line 412, in register_readline
    if readline.get_history_item(1) is None:
  File "c:\python\lib\site-packages\pyreadline-2.0-py3.4-win-amd64.egg\pyreadline\rlmain.py", line 154, in get_history_item
  File "c:\python\lib\site-packages\pyreadline-2.0-py3.4-win-amd64.egg\pyreadline\lineeditor\history.py", line 52, in get_history_item
IndexError: list index out of range

It seems I don't yet have any history, and it seems that site.py is expecting get_history_item() to return None when no history is present, but the pyreadline 2.0 implementation does no such thing, but instead tries to index the history array directly, causing the IndexError.