I have a directory path malfunctioning in some computers in a python program

I have a directory path malfunctioning in some computers in a python program

So I have been building a text based game in python as a project for
learning python, implementing things as I learn them, so I started getting
this error in some cases, I have been developing this game on a raspberry
pi, on a machine running mint 13 and on an android tablet. Lately though I
rebuilt the game in python 3.3, when I did that I started getting an error
when I go to open from a directory path the code is this
with open('rooms/' + str(id) + '.json', 'r', ) as f:
jsontext = f.read()
I store my rooms as json files in a separate folder in the same directory
that the project lies in if any one would like to see how this works you
can check out the project over at www.github.com/kevin2314/TextGame. On
both my raspberry pi and on my mint 13 machine this code works just fine
but on my android tablet, it returns an error like this
IOError: [Errno 2] No such file or directory: "rooms/intro.json"
At first I thought this might have just been because it was on android and
it's not specifically built for programming in python so I didn't pay much
attention to it. After I released it to github though, another person had
the same issue except they were using Ubuntu, So I'm at a loss as to what
the issue is with the path.
If any one can shed some light on this I'd be grateful I wouldn't like to
start having this problem with a lot of people