Drupal 5.1 update stops FCKeditor popup

Hello and thank you for bringing FCKeditor to Drupal. Upgraded to Drupal 5.1 and the "Use FCKeditor in a popup window" feature stopped working. By this I mean when clicking the "Open rich editor" link nothing would happen. I unchecked the "Use FCKeditor in a popup window" and all seemed to work properly as an "in-line" editor. I backed off the Drupal 5.1 upgrade and the popup feature worked fine. Please let me know if you need additional information.