That is your problem right there... the python bitcoin libraries and the script itself are NOT compatible with Python 3... you need to use Python 2.7.x... and from memory it needs to be Python 2.7.9+...
Install Python 2.7, install the required libraries again (making sure you're installing to Python 2!), and you should be able to get the script to run

NOTE: it is also possible, that your wallet file is totally corrupted, so your "100% correct password", won't help you. I've tried assisting other users in the past who had files that wouldn't decrypt properly due to the files being corrupted by MultiBit itself

ps. Try not to cross-post in the future... it'll make things very confusing and you'll get answers all over the place. Try and keep it in one thread!
