period_range fails on python 2.7 (works on python 3.2) - 'str' object has no attribute 'read'
I am doing an exemple from http://pandas.pydata.org/pandas-docs/stable/timeseries.html

rng = pandas.period_range('1/1/2011', periods=500, freq='M')

---

DateParseError                            Traceback (most recent call last)
/home/users/pawel/AGH/mgr/dane/gazowe/<ipython-input-4-a54f4f8b58b5> in <module>()
----> 1 rng = pandas.period_range('1/1/2011', periods=500, freq='M')

/usr/lib64/python2.7/site-packages/pandas/tseries/period.pyc in period_range(start, end, periods, freq)
   1064     """
   1065     return PeriodIndex(start=start, end=end, periods=periods,
-> 1066                        freq=freq)
   1067 
   1068 def _period_rule_to_timestamp_rule(freq, how='end'):

/usr/lib64/python2.7/site-packages/pandas/tseries/period.pyc in **new**(cls, data, ordinal, freq, start, end, periods, copy, name, year, month, quarter, day, hour, minute, second)
    533                 fields = [year, month, quarter, day, hour, minute, second]
    534                 data, freq = cls._generate_range(start, end, periods,
--> 535                                                     freq, fields)
    536         else:
    537             ordinal, freq = cls._from_arraylike(data, freq)

/usr/lib64/python2.7/site-packages/pandas/tseries/period.pyc in _generate_range(cls, start, end, periods, freq, fields)
    551                 raise ValueError('Can either instantiate from fields '
    552                                  'or endpoints, but not both')
--> 553             subarr, freq = _get_ordinal_range(start, end, periods, freq)
    554         elif field_count > 0:
    555             y, mth, q, d, h, minute, s = fields

/usr/lib64/python2.7/site-packages/pandas/tseries/period.pyc in _get_ordinal_range(start, end, periods, freq)
    925 
    926     if start is not None:
--> 927         start = Period(start, freq)
    928     if end is not None:
    929         end = Period(end, freq)

/usr/lib64/python2.7/site-packages/pandas/tseries/period.pyc in **init**(self, value, freq, ordinal, year, month, quarter, day, hour, minute, second)
     98                 value = str(value)
     99 
--> 100             dt, freq = _get_date_and_freq(value, freq)
    101 
    102         elif isinstance(value, datetime):

/usr/lib64/python2.7/site-packages/pandas/tseries/period.pyc in _get_date_and_freq(value, freq)
    382 def _get_date_and_freq(value, freq):
    383     value = value.upper()
--> 384     dt, _, reso = parse_time_string(value, freq)
    385 
    386     if freq is None:

/usr/lib64/python2.7/site-packages/pandas/tseries/tools.pyc in parse_time_string(arg, freq)
    217         return ret, parsed, reso  # datetime, resolution
    218     except Exception, e:
--> 219         raise DateParseError(e)
    220 
    221 def _try_parse_monthly(arg):

DateParseError: 'str' object has no attribute 'read'

Works fine with python-3.2.
python-2.7.3, numpy-1.6.2, scipy-0.10.1, pandas 0.8.0
