usaepay fix

On line 11 it says

<pre>
echo '<form  method="post" name="payment_form" action="https://sandbox.usaepay.com/interface/epayform/">';
</pre>

Change the sandbox to www so it reads

<pre>
echo '<form  method="post" name="payment_form" action="https://www.usaepay.com/interface/epayform/">';
</pre>