Python Pandas datetime

[nuncio]

I have some data which I read in pandas like this

data = pd.read_table('filename.txt', sep='  ',index_col=None,engine='python')

The first column is date time in the format 120631135243(YYMMDDhhmmss).
I would like to convert this to a proper date time in the format YY MM DD hh:mm:ss

I tried this

date1=datetime.datetime.fromtimestamp(data2/1e3)

where data2 is data.iloc[1:,0], the first column of the file
but resulted in this error

Error:
TypeError                                 Traceback (most recent call last)
<ipython-input-74-a215186a1d9c> in <module>()
----> 1 date1=datetime.datetime.fromtimestamp(data2/1e3)

/home/nuncio/anaconda2/lib/python2.7/site-packages/pandas/core/series.pyc in wrapper(self)
    78             return converter(self.iloc[0])
    79         raise TypeError("cannot convert the series to "
---> 80                         "{0}".format(str(converter)))
    81 
    82     return wrapper

TypeError: cannot convert the series to <type 'float'>

Any suggestions
thankyou