I can't think of a reason why Poser would throw a hissy fit by importing an obj file, even if it was a poorly made obj file (not saying that yours was)...unless you are importing a huge poly model. But let's just say that it's an average poly model and it has lots of n-gons...you should only have issues when you are rendering it, not just importing it.
So I would look elsewhere for your problem on importing. Maybe it does have to do with the OpenGL setting, try it without. But also keep an eye on your poly count just in case.

I'm running XP Pro x64 bit with a Nvidia 9800 gtx and can import some pretty hefty models (I just can't say no to chamfering when I model! )

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