Error when subtracting mixed type DataFrame
Sample code to reproduce the error:

import numpy as np
import pandas

X = np.random.rand(10,10)
Y = np.ones((10,1),dtype=int)
df1 = pandas.DataFrame(X)
df1 = df1.join(pandas.DataFrame(Y),lsuffix='.X')

print df1-df1.mean()

---

Traceback (most recent call last):
  File "pls_model.py", line 383, in <module>
    run(df)
  File "pls_model.py", line 305, in run
    report(df.copy(),n_comp,priors=priors,plot=False)
  File "pls_model.py", line 83, in report
    plsgnb.fit(X,Y,priors=priors)
  File "C:\src\multivariate\src\multivariate\PLS.py", line 477, in fit
    self.model.fit(X,Y)
  File "C:\src\multivariate\src\multivariate\PLS.py", line 145, in fit
    print x - self.Xmean
  File "C:\src\pandas\pandas\core\frame.py", line 177, in f
    return self._combine_series(other, func, fill_value, axis, level)
  File "C:\src\pandas\pandas\core\frame.py", line 2526, in _combine_series
    return self._combine_series_infer(other, func, fill_value)
  File "C:\src\pandas\pandas\core\frame.py", line 2541, in _combine_series_infer
    return self._combine_match_columns(other, func, fill_value)
  File "C:\src\pandas\pandas\core\frame.py", line 2552, in _combine_match_columns
    left, right = self.align(other, join='outer', axis=1, copy=False)
  File "C:\src\pandas\pandas\core\frame.py", line 1735, in align
    method=method)
  File "C:\src\pandas\pandas\core\frame.py", line 1804, in _align_series
    return (left_result.fillna(fill_value, method=method),
  File "C:\src\pandas\pandas\core\frame.py", line 2426, in fillna
    new_data = self._data.fillna(value)
  File "C:\src\pandas\pandas\core\internals.py", line 938, in fillna
    new_blocks = [b.fillna(value) for b in self.blocks]
  File "C:\src\pandas\pandas\core\internals.py", line 211, in fillna
    new_values.flat[mask] = value
ValueError: cannot convert float NaN to integer
