OK, lets see if I can help you out here, I just did this tomb a few weeks ago and had some trouble with it at first as well. Follow these instructions and see if they work for ya!
1) Examine the torch on the wall over the BLUE part of the floor. Then pull the torch.
2) A floor switch should appear, so step on that.
3) Examine and then pull the torch on the wall over the RED part of the floor.
4) A new floor switch should appear - step on that one and the door should fly right open!
Good luck adventuring!