3ds max says invalid name for bump files

sorry for double post, but i think i posted the other one on the wrong place.I installed FSX sdk sp2, and i have 3ds max 2008, so after configuring the sdk paths and getting the aces tools working, i created a simple box on 3ds max, assigned a fsx material, and to the top polygon, i assigned a different material. both materials have bump maps, but when i try to verify my model using aces tools, i get this message:(i already fixed the lod name problem)that happened to me with different machines. i tried everything.if i only apply one material to the object, it works, the problem lies when i assign 2 different materials, for different parts of my object.any ideas what could this be?thanks in advance.