cant follow you at all

the 1st, create a origin and a hit
and subtract them
like this

Code:
vec_set(vec_origin,vector(player.x,player.y,player.z));
vec_set(vec_hit,hit.x);
vec_sub(vec_hit,vec_origin);

and store its length like this?
Code:
var length=vec_length(vec_hit);
var distance=50;

//how to go on?
vec_normalize(length,distance);
vec_add(vec_origin,length);

anyent = ent_create ("ent.mdl",vec_origin,doanything);