Awesome! That did it! Thanks!
Here is my new code:
<?php
/* @var $EM_Event EM_Event */
$people = array();
foreach($EM_Event->get_bookings() as $EM_Booking){
$people[$EM_Booking->person->ID] = $EM_Booking->person;
$user_info = get_userdata($referring_user_id);
}
?>
<ul class="event-attendees">
<?php foreach($people as $EM_Person): ?>
<li>
<?php $user_info = get_userdata($EM_Person->ID);
echo get_avatar($EM_Person->ID, 50) . " " . $user_info->first_name . " " . $user_info->last_name . " " . $location = xprofile_get_field_data( 'Ort', $EM_Person->ID, $multi_format = 'comma' ) ;
?></li>
<?php endforeach; ?>
</ul>
