The splitting is meant for testing only.
I would implement a key action to test whether the bone rotation updates at all.

I don't understand why you use the variables instead of the vectors.

This part isn't necessary:

player_x = player.x;
silver_x = silver_surfer.x;
silver_pan = silver_surfer.pan;

But, if you want to use the variables, you should declare them this way:

var player_x[3];
var silver_x[3];
var silver_pan[3];

They have to be vectors, that means, they need an array of 3, if you use them with the vector instructions vec_set, vec_add etc..