well, you can try the shadow system of shade-c, i think it would look great on this, you could also make a VERY low poly version of your model. that would be the next LOD stage and would cast the shadow

So far as i can see at the debug Panel it is not the Shadow, it is the entities. Have a look at the second column at the second position: ent is very high. Try first to load an other (smaller) entity for test...