PHP stops on "new AnetApi..."

[steve2301]

In my php I have 

use net\authorize\api\contract\v1 as AnetAPI;



...

function createAnAcceptPaymentTransaction($amount)
{

   $merchantAuthentication = new AnetAPI\MerchantAuthenticationType();

The above line is where it stops. I'm new to PHP. I am not seeing any error messages.

I'm working with the code from    AuthorizeNet/sdk-php

The above page needs to process the result from Authorize.net

Suggestions?

TIA

steve2301