Poser will not ask you which hand when saving, since Hand Poses are universal. On XP 64, but not on Vista, I did encounter a message applying the Pose to the Left Hand, but the Pose applied correctly.

I will add, that no matter if I posed the left hand or the right hand and saved to the Pose Library, they worked.

This might be specific to a figure.

If you are creating the Pose on the Left Hand, try creating it on the Right(or use Symmetry to move it to the Right to Save and see if the issue is still there. There is a bug with saving poses created on the Left Hand for some figures.

ratscloset
aka John