Use stomp and click Face Sorting >By Materials. That should fix it. Complex obj files often have hundreds of redundant material references inside that cause havoc with firefly only on some systems.

This was the original realization about obj's and using Stomp to fix it.
http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2228908&page=1

-Anton, creator of Apollo Maximus
"Conviction without truth is denial; Denial in the face of truth is concealment."

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