Skyrim puzzle ? I need help

I cannot do this reflecting light puzzle in the revealing the unseen quest in Skyrim. I understand that you use frostbite spell and flames spells to move the crystal, but sometimes it doesn't work, nothing seems to happen. Can someone please help me. Also how do you use scrolls in the game. You quip them, then what? I would appreciate anyone help. I have the Xbox 360 version. I understand there some sort of bug/ glitch on this stage in Skyrim.

@time: http://elderscrolls.wikia.com/wiki/Revealing_the_Unseen