When I try to configure the Xinha plugin CSS I get at [host]/admin/settings/htmlarea/plugins/css following error:

Fatal error: Call to undefined function: form_textfield() in /home/icchp/httpd/htdocs_2008/modules/htmlarea/htmlarea.module on line 508

As far as I can see this method is from Drupal 4.x but does not exist in Drupal 5.x anymore.

I use Drupal 5.2 with HtmlArea 5.x-2.0 and Xinha 0.931.