Error message displayed after User registration

Error in Drupal 6 installation, with User Badges 6.x-1.6 is shown after user registers.

key_exists() expects parameter 2 to be array, null given in /home/Public/domain.com/sites/all/modules/user_badges/user_badges.module on line 244.

Same error has been reported for D7, http://drupal.org/node/1551936 . Will try the solution mentioned there and get back.