[ODE] Slider Joints

[conn@smsc.no]

I have alittle problem when usign slider joints. I want to use two joints
between two objects.
No separatly the joints work really good. But when i try to use both
joints, ever thing explodes, and odemath prints out an error message
saying theres a zero vector.
Both joints is set with out any parameters.
Now i have tried the same with hinge joints and i works really good.
Anyone know why i get this error?