Autocomplete for Registering Other Account not working

The autocomplete function is not working for the User field when creating an "Other account" registration, unless the active user has the Administrator role assigned.

The associated modules are:
Entity Registration 7.x-1.6
Entity Registration Views 7.x-1.6
Real Name 7.x-1.2

Autocomplete works for all authenticated users everywhere on the site except on the Entity Registration "Other Account" page. The field shows up but the autocomplete doesn't work. If the same user is given administrator privileges the autocomplete function works properly for the same event.

HTML generated for Administartor

<div class="form-item form-type-textfield form-item-user">
  <label for="edit-user">User </label>
 <input type="text" id="edit-user" name="user" value="" size="30" maxlength="60" class="form-text form-autocomplete" /><input type="hidden" id="edit-user-autocomplete" value="http://submissions.sarniaphotoclub.com/index.php?q=user/autocomplete" disabled="disabled" class="autocomplete" />
<div class="description">Select a user by typing their username to get a list of matches.</div>
</div>

HTML generated for Authenticated User

                <div id="block-system-main" class="block block-system no-title" >  
  
  <form action="/node/687/register" method="post" id="registration-form" accept-charset="UTF-8"><div><div class="registration-who-msg">You are registering: <em class="placeholder">Other account</em></div><div class="form-item form-type-textfield form-item-user">
  <label for="edit-user">User </label>
 <input type="text" id="edit-user" name="user" value="" size="30" maxlength="60" class="form-text" />
<div class="description">Select a user by typing their username to get a list of matches.</div>
</div>