My custom model's animation won't show up in-game

I've been following Magos' tutorial but I've run into a problem. The models and their textures have been imported into WE fine, but the animations I created in Gmax did not come with them for some reason. In fact, it's worse than that.

I saw the checklist bulletpoint:
I animated my model but it isn't animated in-game?
Did you create a skin modifier on the meshes? Did you make the envelope selection circle large enough?

By skin modifier I assume Magos means bones. Let me tell you about my model. It is a helicopter with spinning rotors. I used a single bone to move the rotors in Gmax, making them all a geoset in the process. I noticed that geosets would not be created without a modifier but I did not need any more animations so I didn't make any more bones. Instead, I modified each primitive very slightly by tapering them so that they would become geosets and I could export.

Fast forward to my problem. The heli body shows up, but the rotors--the group with the bone--is completely detatched from it. It basically hovers in midair and doesn't spin, even though I have it spinning in Gmax at 960 frames just fine. It also has some very strange behavior. When I move a different unit underneath the rotors they sometimes attach to its overhead point and bobble along with the unit's head. Very odd.

I guess my question is, do all the geosets need to be connected by bones to make an animated model work in-game? And if so, how can I make the rotors spin but not the body? Won't they all spin if connected together with bones? Can anyone shed some light? Any help is appreciated.
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I made a movie to show what is wrong.

SEE IT HERE: http://tinyurl.com/h4qqd

Please read our Rules and don't double post. I have merged your posts.

I do not know much about Gmax, sorry.