80% of the time when having different files for my codes I tend to miss the proper pointer which cause the error. There are also times where in pointer player isn't recognize right away after pointing your entity as the player and calling a function that use player pointer. It would help to wait until player pointer exist before executing your code like.
void goto_encounter()
{
while(!player){wait(1);}
player.x = 0;
player.y = 0;
player.z = -300;
}
