Joints going ape-sh*t

Hi again, I'm (as usually) haveing some troubles, this time with joints. Im playing around with joints and when i make a chain (a series of bodies connected with a ball-and-socket joint that is) in +Y i get this result:

and then after a short while this:

why does it do this and how could i solve it?

(if its not possible to see it in the pictures its the joints between the bodies that goes crazy and starts jumping around and behaving erratic(sp?))

are the nodes making up the rope setup as a hierarchy (rootnode->first segment->second segment-> etc...) ?

I just had a similar problem. Attaching every node to the rootSceneNode solved it.

e.g.
rootSceneNode->firstSegment
rootSceneNode->secondSegment
rootSceneNode->thirdSegment
etc ...

bbye,
Sammy