Did you ZERO out the figure before Exporting from Poser?

Do:
Remove all IK
Zero joints with the joint editor.
Select body, Set X,Y and Z trans at 0.000
Slect hip , Set X,Y,Z trans at 0.000
Select body again, Cross chack that X,Y,Z, trans are still at 0.000

Export head as morph target.

Do NOT:
Move the head around in Blender.
Onyl move the vertex you want to morph.

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!