Someone has to reply!  Most long term Carrara users would ask why in the world would you take anything back to Poser?

Most of us use Poser as a sometimes resource  for Carrara not the other way around! (You will agree in time!)

Anyway, basic rule, other than in a Nurbs type modelling programme, Booleans are allways iffy.
Whenever possible avoid booleans. There are other ways to make things.

Unforunately its just one of those things with non Nurbs apps.
(Though I have been known to be wrong!)

Have fun, Carrara5 is a great 3D app.

bwtr