If you search around a bit Ragecgi has posted a way to open Maya 4.5 files in 4.0, but only if nothing that is only found in 4.5 has been utilized, like Fluids.

Darkon

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Red bellows of flame have blackened my stones
Convulsing my frame and cracking my bones
Hell's dragons of steel who roar in their chains
Crawl into my caves to suck out my veins.....

-The Mountain P.F.M.