After the migration from Joomla 1.7 up to 2.5.6 i get this error message when a new user want's to register. The CB Version is 1.8.1.

Warning: array_keys() expects parameter 1 to be array, null given in /www/htdocs/w00/jm17/administrator/components/com_comprofiler/plugin.class.php on line 442

Warning: Invalid argument supplied for foreach() in /www/htdocs/w00/jm17/administrator/components/com_comprofiler/plugin.class.php on line 442