Okay, I managed to get Malice's function to work for my game. I had to change:
Code:
if(vec_dist(my.x,vec_next_node.x) < my.max_x)
to
if(vec_dist(my.x,vec_next_node.x) < 80)

I also used this c_move() code in my monster_code() action:
Code:
c_move(my, vector(8 * time_step, 0, 0), nullvector, GLIDE);


Now it seems to be working, from what I can tell. Thank you Malice and Superku.