Why is my ImageLabel 'disappearing'?

I have an ImageLabel inside a GUI (on a bus) that shows a decal. Specifics aren't really important to this I feel. There are buttons that are clicked that change the decal on the ImageLabel. However for some reason the code breaks, citing that "ImageLabel is not a valid member of x" The problem is, I've used Merely's online studio and the ImageLabel most certainly is a member of the Frame it is supposed to be in, but for some reason the code thinks it isn't?

Now the most obvious answer would be that I coded it wrong, after all it is script.Parent.Parent.ImageLabel.Image = "blah" but on different buses which show the same HUD, the clicking of the ImageButton works. There is absolutely no reason why it should work on one and not the other and it is very frustrating.

Any ideas as to what could be happening?

MD

EDIT: The code works fine in studio on all of the buses, but online it only works on a few, and its always the same few. When I copy the code into the other bus then it still breaks, but there is no reason why :/