NoMethodError in Lag#index

Showing /home/app/webapp/app/views/lag/index.html.erb where line #91 raised:

undefined method `headline' for nil:NilClass
Extracted source (around line #91):
89
90
91
92
93
94
              
<a name="<%= text2a_name(article.headline).html_safe %>"></a>
<h2></h2>
<div class="a-ingress"></div>
<p class="a-pekere"></p>
<p class="a-dato"></p>

Rails.root: /home/app/webapp

Application Trace | Framework Trace | Full Trace

Request

Parameters:

{"lag"=>"Sentralt",
 "id"=>"507"}

Response

Headers:

None