parentOf error

gistfile1.txt

{% if not user %}
{% redirect "profiel" %}
{% endif %}

{% extends "_layout" %}
{% set title = "Gekoppelde familieleden" %} 
{% set entry = craft.entries.section('registratie').authorId(currentUser.id).first() %}
{% if entry | length == 0 %}
{% set entry = craft.entries.section('registratie').first() %}
{% endif %}

{% set koppelingen = craft.entries.section('registratie').parentOf(currentUser.id).find() %}

{% block main_class %}profiel{% endblock %}

{% block javascript %}
{% endblock %}

{% block content %}

  <div id="breadcrumb">
		<a href="{{ url('') }}">Uitvaartakte.nl</a> &raquo; {{entry.link}}
	</div>
						
	<h1>Gekoppelde familieleden</h1>
	
	<a class="button blue large" href="{{ url('profiel/gekoppeld/toevoegen') }}"><span>+ Familielid koppelen</span></a>
	{% if koppelingen | length %}
	<hr />
	<table>
		<tr>
			<th>Naam</th>
			<th class="right">Uitvaartwensen</th>
		</tr>
	{% for wens in koppelingen %}
		<tr>
			<td>{{ wens }}</td>
			<td class="right"><a href="{{ url('profiel/gekoppeld/bekijk/' ~ wens.slug) }}">Bekijk uitvaartwensen &rsaquo;</a></td>
		</tr>
	{% endfor %}
	</table>
	{% endif %}	
				
{% endblock %}

{% block sidebar %}
{% endblock %}