Gmax object changes shape in FS....

HiI've created an object in Gmax, made up of many rectangles at different angles, and when i exported it into FS, instead of having all the corners meeting at the correct places and the objects remaining the same as in gmax, some of the objects either dissapear, the scale of a few objects becomes MASSIVE and other parts remain normal.I'm wondering what the problem is, i've been using this object for other creations and all i've done is copied it and used it at other locations, and thats where the problem has started.Is it related to scaling?CheersWill