[ODE] Torque instability

[nlin@nlin.net]

Earlier I wrote about instability after applying a torque to a floating
body with no gravity or other forces. I forgot to mention that I apply
exactly ONE torque for ONE timestep, and apply NO torque or forces thereafter.
Still, after several timesteps, the system becomes instable, the box spins
faster and faster, then eventually flies off into "nan" land.

Any ideas why?

-Norman