php Fatal error: Function name must be a string in
<p><strong>Fatal error: Function name must be a string in /home/../public_html/updater.php on line 3</strong></p>

<pre><code> 1: &lt;?php
 2:    
 3: $user_id = $_GET("uid"); /* &lt;-- Line 3 */
 4: $user_name = $_GET("uname");
 5: $setting = $_GET("setting");
 6:    
 7: $MyString = $user_name + '[' + $user_id + ']{' + $setting + '} \n';
 8:    
 9: $myfile = fopen('database.txt', 'a');
10: fwrite($myfile, $MyString . '\n');
11: fclose($myfile);
12:    
13: ?&gt;
</code></pre>

<p><strong>What's the problem ?</strong></p>
