Really you are rendering with pretty conservative settings.  I was thinking you were rendering with very high options e.g. a lot of raytrace bounces or smooth polygons with a very low shading rate, but you're not even using raytracing and your shading rate is set to 1 (and smooth polygons is disabled anyway).  Poser 7 does not behave this way for me, but then again I have Windows XP Pro 64-bit and not Vista 64-bit, which may make a difference.

The only thing I can think of to suggest is to "babysit" poser.exe, and when it grows to 2GB, minimize it, repeating as necessary; there are still some memory crashes that I have been able to avoid using this trick.

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