bug in DataFrame.plot()
I seem to run into a bug in pandas 0.8 with plot().
This is the sequence of commands, the external file that is read can be send to reproduce the exception.

import pandas
s1=pandas.read_table('DATA_serie1.TXT')
dr = pandas.date_range(start='2012-01-01', periods=1500, freq='30Min')
s1.index=dr
s1.plot()

This is the exception trace:
## In [13]: s1.plot()

Traceback (most recent call last):
  File "<ipython console>", line 1, in <module>
  File "C:\Python27\lib\site-packages\pandas\tools\plotting.py", line 693, in plot_frame
    plot_obj.generate()
  File "C:\Python27\lib\site-packages\pandas\tools\plotting.py", line 241, in generate
    self._make_plot()
  File "C:\Python27\lib\site-packages\pandas\tools\plotting.py", line 431, in _make_plot
    self._make_ts_plot(data)
  File "C:\Python27\lib\site-packages\pandas\tools\plotting.py", line 492, in _make_ts_plot
    tsplot(data[col], plotf, ax=ax, label=label, *_kwargs)
  File "C:\Python27\lib\site-packages\pandas\tseries\plotting.py", line 111, in tsplot
    plotted = plotf(ax, *args,  *_kwargs)
  File "C:\Python27\lib\site-packages\matplotlib\axes.py", line 3783, in plot
    for line in self._get_lines(_args, *_kwargs):
  File "C:\Python27\lib\site-packages\matplotlib\axes.py", line 317, in _grab_next_args
    for seg in self._plot_args(remaining, kwargs):
  File "C:\Python27\lib\site-packages\matplotlib\axes.py", line 294, in _plot_args
    x, y = self._xy_from_xy(x, y)
  File "C:\Python27\lib\site-packages\matplotlib\axes.py", line 210, in _xy_from_xy
    bx = self.axes.xaxis.update_units(x)
  File "C:\Python27\lib\site-packages\matplotlib\axis.py", line 1256, in update_units
    converter = munits.registry.get_converter(data)
  File "C:\Python27\lib\site-packages\matplotlib\units.py", line 132, in get_converter
    for thisx in x:
  File "C:\Python27\lib\site-packages\pandas\tseries\period.py", line 687, in __iter__
    yield Period(ordinal=val, freq=self.freq)
  File "C:\Python27\lib\site-packages\pandas\tseries\period.py", line 138, in **init**
    raise ValueError('Only mult == 1 supported')
ValueError: Only mult == 1 supported

I will send the file to wes on his personal e-mail address, unless I can add it to this issue somehow?
thanks,
roel
