[ODE] new assert in box.cpp

[Irrisor]

Hi,

box.cpp was changed recently and now contains these lines:

   if (cnum < 1) {
	  dIASSERT(0);
	  return 0;	// this should never happen
   }


The problem with this is: it does happen!
Oleh, do you have an idea why? I checked for NaNs in the local vars but does not 
seem to be the problem...

/Irrisor