Scratch

Hey guys. I've recently been aske dot make a Scratch project as part of an assignment I'm producing for the first year of my Computing Games Technology degree, however I have encountered a bug in the software. Basically, I'm making a 'lights out' style game, whereas the user has to solve a puzle by making all the boxes shown on screen the same colour.

I acheived this by using 25 clickable sprites that simply change costume and broadcast a message when clicked, and by having the stage detect whether all the sprites are of the same costume to move to the next level. However, one of the sprites has ceased to 'work', and I can;t figure out which one.

There is a sprite displayed on the top-right of the grid, which can not be moved, clicked, or seen, and doesn't appear as part of all the other resources on the bottom right. Double-clicking this sprite simply opens the stage, which this sprite is not part of either. Obviously, aside from being an eye-sore, this is very confusing to the user in terms of the game. And I can;t figure out how to get rid of it.

I've uploaded my Scratch project file here, as while I don't think I can reproduce the glitch, the glitch still stays if the file is closed and reopens. It seems to be assciated with this particular file.

Scartch Project file:
http://www.mediafire.com/?g76o6rhch27o86o

Anwyay, I could really do with some help with this, since the assignment is due in tommorow night. Any ideas, guys?
Regards, Andrew.