Ill verify this same error when adding a user to a group :

Warning: Wrong parameter count for array_unique() in ....../concrete/core/controllers/single_pages/dashboard/users/search.php on line 171

Warning: Cannot modify header information - headers already sent by (output started at ....../concrete/core/controllers/single_pages/dashboard/users/search.php:171) in /home/users/uks66418/html/dev/ckuk2/concrete/core/libraries/view.php on line 901

Adding a user i occasionaly get :

An unexpected error occurred.
mysql error: [1048: Column 'pUID' cannot be null] in EXECUTE("INSERT INTO LWPostings(pID,pptID,pUID,pShareWith,pData,pCreateDate,pDeleteDate,toUID,pSubjectType,pSubjectID,pOnObjectType,pOnObjectID,pLevel) VALUES (NULL,'1',NULL,'2','a:1:{i:0;s:0:\"\";}','2012-10-30T01:24:34+0000',NULL,'','User','6','','','1')")

POSTED BUG:
http://www.concrete5.org/developers/bugs/5-6-0-2/add-change-user-gr...

I am getting same error same place when adding or saving changes to a user

Warning: Cannot modify header information - headers already sent by (output started at /home/novologic/sites/triadmechanical.com/htdocs/offers/concrete/core/controllers/single_pages/dashboard/users/search.php:171) in /home/novologic/sites/triadmechanical.com/htdocs/offers/concrete/core/libraries/view.php on line 901