title: Error in getting fitted values
body: <p>I am having problems getting the fitted values from a linear mixed model (<code>lmer()</code>). Normally I would use <code>fitted()</code> but I am getting this error:</p>
  
  <blockquote>
    <p>Error: $ operator not defined for this S4 class</p>
  </blockquote>
  
  <p>Is there another way to get the fitted values, or can anyone explain my why I am getting that error?</p>
  
  <p>I am using R version 3.0.1.</p>
  
  <p>Hope someone can help.</p>