Hi everybody!
I finally started messing around with the physics engine but somehow it doesn't work. I set the global gravity according to the manual and attach this to some map entities that I placed above each other with some minor changes in rotation and position:

ACTION box {
phent_settype(my,PH_RIGID,PH_BOX);//register entity with physics
phent_setdamping(my,50,50);//set physics damping
phent_setfriction(my,0);
phent_setmass(my,10,PH_BOX);//set box to 10 kg weight
phent_setgroup(my,2);
phent_setelasticity (my,50,25);//just playing around
}

The boxes fall a short time and then all boxes except for the lowest fall into the lowest box and into each other. And then their position gets a bit higher and they fall and rise and fall and rise and fall and... You get the idea... Could somebody please tell me what I'm missing?

you shouldn't use phent_setgroup in this example! entities within the same group don't collide with each other!

Ooops... I knew it had to be something simple... Thanks!