Using mle function to fit cdf data

Hi all,

I have test data (x and y values) that fall along a cdf plot. I want to fit these x and y values with a normcdf using the mle function in MATLAB. No matter what I've tried, I get an error. Help?

Here's the code that I'm using:

function phat = mle_test

%Test data
x = 1:100;
mu = 5;
sigma = 5;
y = normcdf(x,mu,sigma);
data = [x,y];

%Generate maximum likelihood estimate
phat = mle(x,'pdf',@pdf_norm,'cdf',@cdf_norm,'start',[5,5]);

%Plot raw data
plot(x,y,'o');
hold on

%Create fit
yfit = normcdf(x,phat(2),phat(1));

%Plot fitted data
plot(x,yfit,'r-')

function pdf_norm(x,mu)
sigma = 5;
normpdf(x,mu,sigma)

function cdf_norm(x,mu)
sigma = 5;
normcdf(x,mu,sigma)

Any help is greatly appreciated! Thanks!