title: unexpected T_CONCAT_EQUAL
body: <p>I'm getting an unexpected T_CONCAT_EQUAL error on a line of the following form:</p>
  
  <pre><code>$arg1 .= "arg2".$arg3."arg4";
  </code></pre>
  
  <p>I'm using PHP5.  I could simply go an do the following:</p>
  
  <pre><code>$arg1 = $arg1."arg2".$arg3."arg4";
  </code></pre>
  
  <p>but I'd like to know whats going wrong in the first place.  Any ideas?</p>
  
  <p>Thanks,
  sweeney</p>