loading and controling a chracter.

Helo guys.

Need some help with loading and animating a character. Maybe im going about it all wrong but here is what i have so far.

Created a humanoid character in 3dmax added bones ( head to toe ) exported as obj / ase (i have both files)
created a chracter class like the tankase example but when i run i get athis error:

Exception in thread “main” java.lang.IllegalArgumentException: This Node already has a parent.
at org.xith3d.scenegraph.GroupNode.addChild(GroupNode.java:142)

the error id from this line

Bone_Head.addChild((Node)nodes.get(“Bone_Head”));

anyhelp will be appreciated. Is there anywhere i can get TUTORIAL on loading and controling individual parts of a model?