Selenium fejlmeddelse

Helt ny i Python og er godt igang med en tutorial, men alligevel skal jeg jo lege lidt med noget andet samtidig og ville lave et program der kan åbne Firefox, og fandt en side der beskrev hvordan jeg nemt installerede Selenium:

https://www.seleniummaster.com/sitecontent/index.php/selenium-web-driver-menu/selenium-test-automation-with-python/186-how-to-install-selenium-python-webdriver

men jeg får alligevel en fejl selv om at jeg har fulgt den grundigt, fejlen er denne:

Python 3.4.0 (v3.4.0:04f714765c13, Mar 16 2014, 19:25:23) [MSC v.1600 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from selenium import webdriver
>>> browser=webdriver.Firefox()
Traceback (most recent call last):
  File "C:\Python34\lib\site-packages\selenium\webdriver\common\service.py", line 76, in start
    stdin=PIPE)
  File "C:\Python34\lib\subprocess.py", line 848, in __init__
    restore_signals, start_new_session)
  File "C:\Python34\lib\subprocess.py", line 1104, in _execute_child
    startupinfo)
FileNotFoundError: [WinError 2] Den angivne fil blev ikke fundet

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python34\lib\site-packages\selenium\webdriver\firefox\webdriver.py", line 164, in __init__
    self.service.start()
  File "C:\Python34\lib\site-packages\selenium\webdriver\common\service.py", line 83, in start
    os.path.basename(self.path), self.start_error_message)
selenium.common.exceptions.WebDriverException: Message: 'geckodriver' executable needs to be in PATH.

>>> browser.get('http://www.google.com')
Nogen der kan hjælpe :-)