'int' object has no attribute '__getitem__'

[xmillion]

1230 14:42:21291 :: Traceback (most recent call last):

1230 14:42:21291 :: File "game.py", line 1473, in OnKeyDown

1230 14:42:21291 :: File "game.py", line 406, in <lambda>

1230 14:42:21291 :: File "interfaceModule.py", line 2166, in OpenTrackWindow

1230 14:42:21291 :: File "interfaceModule.py", line 2164, in MakeTrackWindow

1230 14:42:21291 :: File "uiTrack.py", line 187, in __init__

1230 14:42:21291 :: File "uiTrack.py", line 360, in __LoadWindow

1230 14:42:21291 :: File "uiTrack.py", line 385, in SetTrackType

1230 14:42:21292 :: File "uiTrack.py", line 398, in Refresh

1230 14:42:21292 :: File "ui.py", line 2669, in RefreshAll

1230 14:42:21292 :: TypeError
1230 14:42:21292 :: :
1230 14:42:21292 :: 'int' object has no attribute '__getitem__'
1230 14:42:21292 ::

Def in ui

def RefreshAll(self):
windowHeight = self.GetHeight()
scrollBar = self.scrollBar
screenSize = 0
for child in self.itemList:
child.exPos = child.GetGlobalPosition()[0]
if child.exPos[1] > screenSize:
screenSize = child.exPos[1]
if screenSize > windowHeight:
scrollLen = screenSize-windowHeight
if scrollLen != 0:
scrollLen += self.scrollLenExtra
self.scrollLen = scrollLen
scrollBar.SetMiddleBarSize(float(windowHeight-5)/float(screenSize))
else:
scrollBar.SetMiddleBarSize(1.0)

error line

if child.exPos[1] > screenSize:
screenSize = child.exPos[1]