struct.error: unpack requires a string argument of length 2

问题

I have this following code it works 64bit another computer but it does not work with mine and gives the fallowing error.I use Python 3.3 and the requiered libraries. I could not solve the problem please help.

import matplotlib.pyplot as plt
import binascii
import numpy
import struct

array = []
out = open('output.txt','wb')

a=int(input("Enter the first value:"))
b=int(input("Enter the second value:"))

with open("thefile.bin", "rb") as f:

    i=0 
    for i in range(0, a):
        byte = f.read(1)

    i=0
    for i in range(a,b):
        byte = f.read(1)
        value = struct.unpack('B', byte)[0]
        array.append(value)


plt.plot(array)
plt.ylabel('Value')
plt.show()

来源：https://stackoverflow.com/questions/17579444/struct-error-unpack-requires-a-string-argument-of-length-2