Fatal error: Class 'PEAR' not found in /usr/share/pear/Text/Wiki.php on line 412

I have got this message when save wiki-formatted post (with interwiki-links):

Fatal error: Class 'PEAR' not found in /usr/share/pear/Text/Wiki.php on line 412

This is because class in Text/Wiki.php does not extend class Pear so this class should be included in your module.

To fix this find line 468 in pearwiki_filter.module:

   @include_once 'Text/Wiki.php';

and replace with:

   // needed for error checking
   @require_once 'PEAR.php';
   @include_once 'Text/Wiki.php';

That's all. Thanks for your good work!