Shoutbox

Here I come with another trouble that only happens to Vista users...
One fine happy day, my scroolbars were working pretty fine, looked like I wanted (Vista-copy, in another words).
Other fine happy day, the "up" and "down" and "bottom" arrows simply disapeared, and also that thingy on the half.
Then, another happy fine day, decided to activate my "Disable custom scroolbars" code, and for my surprise, the default ones disappeared too! =D
Any ideas of what it could be?
File at: SkyDrive

Edit: Nothing?!