Error in CiviCRM for Drupal7 after Migrate from "Backup and Migrate" module on New Contact Form
I figured out what happened. When I did the backup and migrate, Drupal set civicrm_tag.used_for to NULL. I set the field for all my tags to 'civicrm_contact' and it fixed the problem. No more errors. I just ran this query:
UPDATE civicrm_tag SET used_for='civicrm_contact';