Thanks! My problem is solved :]

I have another problem.. not sure if I start another topic to ask this but, I can't change the friction value of triangle[i]! Weird..
In the entity's action, I set up the pointer:
...
triangle[k] = me; //k is a global variable
pivotobj[k] = phcon_add(PH_SLIDER, me, you);
...

And inside a function (executated in main) I have:
...
phcon_setmotor(pivotobj[i], strength, nullvector, nullvector); //This one works!
phent_setfriction (triangle[i], friction_value); //this is the problematic line
...

When the code is running I get a message saying "empty pointer in main".