When you checked the rotations, I meant for you to check the rotation orders. At the bottom of the joint editor you will see three letters XYZ and they may be in any order YZX, ZYX etc. Those three letters should be in the same order as listed for your hand on all the finger joints. If you have to change them there is a drop down list with different options. You should make those changes with the joint editor in the setup room because sometimes in the pose room your mesh will explode when you do it there. Your hand bone shouid be aligned with the arms with the endpoint towards the fingers.

I don't know what else to check if it is not the parenting or the joint rotation order. They dont happen to have any IK chains do they?

Edit:  If they are conforming, the bones centers, endpoints, and joint rotation orders must match their host figure exactly in every way, including the mat spheres, for each and every matching bone of the figure you are conforming them to. I hope that made sense. :)

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A HOMELAND FOR POSER FINALLY