Terquel Source v 0.01 NOT WORKING

#encoding: utf-8
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label
from kivy.uix.button import Button
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.checkbox import CheckBox
from kivy.uix.scrollview import ScrollView
from kivy.properties import StringProperty
import random
import zlib
import os.path
import marshal
import time

class MainScreen(Screen):

    pass

class ScrollableLabel(ScrollView):
    text = StringProperty("")

class Terquel(App):

    def read_presentation(self):
        file = open("main.tq", "rb")
        presentation_data = file.read()
        file.close()
        presentation_data = presentation_data.split("\n")
        currentslide = 1
        for i in presentation_data:
            cmd = i.split(" ")
            if cmd[0] == "slides":
                slidesnr = int(cmd[1])
                # Make a class for each slide
                for i in range(1,slidesnr):
                    self.manager.add_widget(Screen(id="Slide"+str(i)))
            elif cmd[0] == "slide":
                currentslide = int(cmd[1])
            elif cmd[0] == "label":
                labelid = str(cmd[1])
                cmd[0] = ""
                cmd[1] = ""
                labeltext = "".join(cmd)
                nextlabel = Label(id=labelid, text=labeltext)
                self.ids["Slide"+str(currentslide)].add_widget(nextlabel)
            elif cmd[0] == "image":
                imageid = str(cmd[1])
                imagesrc = str(cmd[2])
                nextimage = Image(id=imageid,source=imagesrc)
                self.ids["Slide"+str(currentslide)].add_widget(nextimage)

    def build(self):
        Builder.load_file("main.kv")
        sm = ScreenManager()
        sm.add_widget(MainScreen(name='main'))
        self.read_presentation()
        return sm

if __name__ == "__main__":
    Terquel().run()