Matplotlib Error: LaTeX was not able to process the following string: 'lp'

This is the error I'm getting from the function I'll provide at the bottom:

'latex' is not recognized as an internal or external command,
operable program or batch file.
Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\python27\lib\lib-tk\Tkinter.py", line 1486, in __call__
    return self.func(*args)
  File "C:\python27\lib\site-packages\matplotlib\backends\backend_tkagg.py", lin
e 278, in resize
    self.show()
  File "C:\python27\lib\site-packages\matplotlib\backends\backend_tkagg.py", lin
e 349, in draw
    FigureCanvasAgg.draw(self)
  File "C:\python27\lib\site-packages\matplotlib\backends\backend_agg.py", line
469, in draw
    self.figure.draw(self.renderer)
  File "C:\python27\lib\site-packages\matplotlib\artist.py", line 59, in draw_wr
apper
    draw(artist, renderer, *args, **kwargs)
  File "C:\python27\lib\site-packages\matplotlib\figure.py", line 1079, in draw
    func(*args)
  File "C:\python27\lib\site-packages\matplotlib\artist.py", line 59, in draw_wr
apper
    draw(artist, renderer, *args, **kwargs)
  File "C:\python27\lib\site-packages\matplotlib\axes\_base.py", line 2092, in d
raw
    a.draw(renderer)
  File "C:\python27\lib\site-packages\matplotlib\artist.py", line 59, in draw_wr
apper
    draw(artist, renderer, *args, **kwargs)
  File "C:\python27\lib\site-packages\matplotlib\axis.py", line 1116, in draw
    renderer)
  File "C:\python27\lib\site-packages\matplotlib\axis.py", line 1065, in _get_ti
ck_bboxes
    extent = tick.label1.get_window_extent(renderer)
  File "C:\python27\lib\site-packages\matplotlib\text.py", line 741, in get_wind
ow_extent
    bbox, info, descent = self._get_layout(self._renderer)
  File "C:\python27\lib\site-packages\matplotlib\text.py", line 311, in _get_lay
out
    ismath=False)
  File "C:\python27\lib\site-packages\matplotlib\backends\backend_agg.py", line
223, in get_text_width_height_descent
    renderer=self)
  File "C:\python27\lib\site-packages\matplotlib\texmanager.py", line 670, in ge
t_text_width_height_descent
    dvifile = self.make_dvi(tex, fontsize)
  File "C:\python27\lib\site-packages\matplotlib\texmanager.py", line 417, in ma
ke_dvi
    report))
RuntimeError: LaTeX was not able to process the following string:
'lp'
Here is the full report generated by LaTeX:

This is the function I'm using that creates the above error:

def Derivative( inputArrayList,rowNumber_from_top ):
    for image in inputArrayList:
        rowValues = image[0][rowNumber_from_top]
        for i in range(len(rowValues)):         
            # Perform the difference derivative estimation
            if i == 0 or i == (len(rowValues) - 1):
                rowValues[ i ] = 0 # set edges to 0
            else:
                derivative = (rowValues[ i+1 ] - rowValues[ i-1 ])/(2.0)
                rowValues[ i ] = derivative
        plt.rc('text', usetex=True)
        plt.rc('font', family='serif')
        plt.plot(rowValues,color="k")
        plt.ylim( (0,image.max() + 10.0) )
        plt.title(r"$\displaystyle\sum_{n=1}^\infty\frac{-e^{i\pi}}{2^n}$")
        plt.show()

Notice the line plt.title(r"$\displaystyle\sum_{n=1}^\infty\frac{-e^{i\pi}}{2^n}$"). I've taken this from the first graph on Matplotlib's site (and I've tried running that program as well that they provide) and I cannot seem to get it to work. I'm almost certain it's a simple fix (like maybe I'm missing a LaTeX module or something?).

The whole goal was to be able to use the command \displaystyle in the title and labels of the plot to make fractions larger.

I apologize if this is a duplicate (although I can't find a similar issue), I just need a pointer to get me going in the right direction.

Thank you for your time,

Brandon