KeyError: 0L with pandas 0.13.1
I get the following error 

``` python
Traceback (most recent call last):
  File "asys.py", line 65, in <module>
    compSub()
  File "asys.py", line 46, in compSub
    plt.hist(data['Total'],linewidth=0, alpha=.7)
  File "/home/storm/Documents/lol/local/lib/python2.7/site-packages/matplotlib/pyplot.py", line 2827, in hist
    stacked=stacked, **kwargs)
  File "/home/storm/Documents/lol/local/lib/python2.7/site-packages/matplotlib/axes.py", line 8249, in hist
    if isinstance(x, np.ndarray) or not iterable(x[0]):
  File "/home/storm/Documents/lol/local/lib/python2.7/site-packages/pandas/core/series.py", line 491, in __getitem__
    result = self.index.get_value(self, key)
  File "/home/storm/Documents/lol/local/lib/python2.7/site-packages/pandas/core/index.py", line 1032, in get_value
    return self._engine.get_value(s, k)
  File "index.pyx", line 97, in pandas.index.IndexEngine.get_value (pandas/index.c:2661)
  File "index.pyx", line 105, in pandas.index.IndexEngine.get_value (pandas/index.c:2476)
  File "index.pyx", line 149, in pandas.index.IndexEngine.get_loc (pandas/index.c:3215)
  File "hashtable.pyx", line 382, in pandas.hashtable.Int64HashTable.get_item (pandas/hashtable.c:6450)
  File "hashtable.pyx", line 388, in pandas.hashtable.Int64HashTable.get_item (pandas/hashtable.c:6394)
KeyError: 0L
```

when I execute the following code(using `pandas 0.13.1`)

``` python
#!/usr/bin/env python
# -*- coding: utf-8 -*-

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
from scipy import stats
import statsmodels.api as sm
from numpy.random import randn
import matplotlib as mpl
import seaborn as sns

sns.set_color_palette("deep", desat=.6)
mpl.rc("figure", figsize=(8, 4))

def Compavg():
    data=Total()
    markMax=[]
    markAvg=[]
    N = 5
    ind = np.arange(N)    
    width = 0.35 
    fig = plt.figure()
    ax = fig.add_subplot(111)      
    markMax.extend((data["Total"].max(),data["Total.1"].max(),data["Total.2"].max(),data["Total.3"].max(),data["Total.4"].max()))
    markAvg.extend((data["Total"].mean(),data["Total.1"].mean(),data["Total.2"].mean(),data["Total.3"].mean(),data["Total.4"].mean()))
    rects1 = ax.bar(ind, markMax, width, color='black')
    rects2 = ax.bar(ind+width, markAvg, width, color='green')
    ax.set_xlim(-width,len(ind)+width)
    ax.set_ylim(0,120)
    ax.set_ylabel('Marks')
    ax.set_title('Max, Mean and Your Marks')
    xTickMarks = ['Subject'+str(i) for i in range(1,6)]
    ax.set_xticks(ind+width)
    xtickNames = ax.set_xticklabels(xTickMarks)
    plt.setp(xtickNames, rotation=10, fontsize=10)
    ax.legend( (rects1[0], rects2[0]), ('Max', 'Mean') )
    plt.show()
    print "finished reading 1"

def compSub():
    #max_data = np.r_[data["Total"]].max()
    #bins = np.linspace(0, max_data, max_data + 1)
    data=Total()
        print data['Total']
    plt.hist(data['Total'],linewidth=0, alpha=.7)
    plt.hist(data['Total.1'],linewidth=0,alpha=.7)
    plt.hist(data['Total.2'],linewidth=0,alpha=.7)
    plt.hist(data['Total.3'],linewidth=0,alpha=.7)
    plt.hist(data['Total.4'],linewidth=0,alpha=.7)
    plt.title("Total marks Histogram")
    plt.xlabel("Value")
    plt.ylabel("Frequency")
    plt.show()
        print "finished reading 2"

def Total():
    print "going to read"
    data=pd.read_csv("output11cs.csv")
    df3=data[['Total','Total.1','Total.2','Total.3','Total.4','Total.5','Total.6','Total.7']]
    data["Main Total"]=df3.sum(axis=1)
    data = data.dropna()
    data.reset_index(drop=True)
    print data  
    return data

Compavg()
compSub()
```

but it works perfectly with pandas version `0.10.0`
