Question: running Maple 13

I'm very new user at Maple. i'm using Maple 13 and wrote a code taking help from another code. i'm writing my code here, i'm receiving error at highlighted line, also i'm unable to get any kind of out put.... plz d help

> newton:=proc(fx,m);
> local i,x0,s,n,x1,k,dfx,fx1,fx2,difference,difference1,x2,d2fx,x3;
> x0:=m;
> n:=128;
> k:=1;
> for i from 1 while i < 500 do
> dfx:=evalf[n](eval[n](diff(f(x),x),x=x0));
> x1:=evalf[n](x0-evalf[n](eval[n](f(x),x=x0))/dfx);
> d2fx:=evalf[n](eval[n](diff(f(x),x),x=x1));
> x2:=evalf[n](x1-evalf[n](eval[n](f(x),x=x1))/d2fx);
> if (evalf[n](abs(x1-x0))<Float(10,-15)) then i:=500;fi;
> end if;
> if (evalf[n](abs(x2-x1))<Float(10,-15)) then i:=500;fi;
> end if;
> difference:=evalf[n](evalf[n](abs(x1-x0)));
> x0:=x1;
> difference1:=evalf[n](evalf[n](abs(x2-x1)));
> x1:=x2;
> k:=k+1; print(x1);print(x2);
> end do;
> print("Sigma=",difference);fx1:=evalf[n](eval[n](f(x),x=x1));print("fxn:=",fx1);
> print("Sigma1=",difference1);fx2:=evalf[n](eval[n](f(x),x=x2));print("fxn1:=",fx2);
> x3:=evalf[28](x2);
> print("Required Result  =",x3);print("in ",k-1);print("Iterations");
> end:
> f(x):=(x-2)^23-1;
> m:=3.5;
> newton(f(x),m);