After updating the Token Panel and Ctools modules I started getting an error:

Notice: Undefined index: name in ctools_token_content_type_content_types()

which was eventually traced to a bad entity type called "comment", or at least one which had no name or description.

http://drupal.org/node/1166796

Disabling the Disqus module made the error disappear.

Cccording to the authors of the Token system, as reported here: http://drupal.org/node/991636

"Usually when we see this error it means there is a module that is not using the upgraded token API for Drupal 7 properly."

So perhaps there is something amiss in the Disqus module causing this error