Tried the example and if there are //// at the bottom of the script it would trow some error. Also if earth.mdl and small.hmp are not inside folder the engine can't find them. Anyways i've made a working demo, you can take a look here.

Try this Code:
////////////////////////////////////////////////////////////////////////////
// small.c - small lite-C example
////////////////////////////////////////////////////////////////////////////
#include <acknex.h> // include these predefined, needed files in our project
#include <default.c>
////////////////////////////////////////////////////////////////////////////
void main()
{
    fps_max = 60;
    // Load the level named "small.hmp"
    level_load("small.hmp");
    // Wait for 3 frames, until the level is loaded
    wait (3); 
    // Now create the "earth.mdl" model at x = 10, y = 20, z = 30 in our 3D world
    ent_create("earth.mdl", vector(10, 20, 30), NULL);
    // NULL tells the engine that the model doesn't have to do anything
}
if your cpu goes wild.

smile