Nested comments don't appear

I'm using Fivestar Extra for comments with the "HOWTO: Hide Comments Below a Certain Rating" patch suggested in the documentation, but now nested comments don't appear. Instead, after posting a nested comment, I'm returned to the /comment/reply/nodeid/commentid address where the one comment I tried to reply to appears. Other users have the same problem. Has this happened to anyone before? Also, when I try to remove the "Hide Comments" patch, I get this error on any page with comments, repeated for the number of comments that are on the node:

warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, 'phptemplate_comment_view' was given in /includes/theme.inc on line 617.

That line is:

$output = call_user_func_array($info['function'], $args);

It's a part of:

  // Include a file if the theme function or preprocess function is held elsewhere.
  if (!empty($info['file'])) {
    $include_file = $info['file'];
    if (isset($info['path'])) {
      $include_file = $info['path'] .'/'. $include_file;
    }
    include_once($include_file);
  }
  if (isset($info['function'])) {
    // The theme call is a function.
    $output = call_user_func_array($info['function'], $args);
  }