When 2 or more objects use the same material and the material uses 2 UV layers and the object that was created last has only 1 UV layer then all objects are forced to use only 1 UV layer when in the game engine.
In the attached file the cylinder was created last. Both it and the center cube have only 1 UV layer. Press the "p" key notice how the normal texture changes. If you delete the Cylinder everything is drawn correctly. The cube dose not effect the other objects because it was not created last.
Windows XP Pro SP3
ATI RADEON 9800 PRO