Warning: array_merge(): Argument #2 is not an array in template.theme-registry.inc on line 74

version = "6.x-2.0"
datestamp = "1277583313"

Similar issue as here #238910: Cant get to the theme page:

( ! ) Warning: array_merge() [function.array-merge]: Argument #2 is not an array in sites/all/themes/zen/zen-internals/template.theme-registry.inc on line 74
#	Time	Memory	Function	Location
1	0.0001	95608	{main}( )	../index.php:0
2	0.0005	107536	drupal_bootstrap( $phase = 8 )	../index.php:17
3	0.0047	151928	_drupal_bootstrap( $phase = 5 )	../bootstrap.inc:1411
4	0.0696	968400	bootstrap_invoke_all( $hook = 'boot' )	../bootstrap.inc:1511
5	0.0779	1195976	module_invoke( 'drupal_tweaks', 'boot' )	../bootstrap.inc:748
6	0.0779	1197320	call_user_func_array ( 'drupal_tweaks_boot', array () )	../module.inc:462
7	0.0779	1198008	drupal_tweaks_boot( )	../module.inc:0
8	0.0816	1349816	t( $string = 'Cannot set variable `%variable` to `%value` in your PHP configuration!<br>Probably you do not have proper privileges.', $args = array ('%variable' => 'max_execution_time', '%value' => '300'), $langcode = ??? )	../drupal_tweaks.module:302
9	0.0818	1351872	theme( 'placeholder', 'max_execution_time' )	../common.inc:931
10	0.0819	1353136	init_theme( )	../theme.inc:606
_theme_build_registry( $theme = class stdClass { public $filename = ...
_theme_process_registry( $cache = array ('status_messages_dt' => array ('arguments' => array ('display' => NULL), 'type' => 'module', 'theme path' => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1', 'function' => 
zen_theme( $existing = array ('status_messages_dt' => array ('arguments' => array ('display' => NULL), 'type' => 'module', 'theme path' => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1', 'function' => 

_zen_theme( $existing = array ('status_messages_dt' => array ('arguments' => array ('display' => NULL), 'type' => 'module', 'theme path' => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1', 'function' => 'theme_status_messages_dt', 'include files' => array (), 'theme paths' => array (0 => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1'), 'preprocess functions' => array (0 => 'template_preprocess')), 'drupal_tweaks_msg_rules_form' => array ('template' => 'msg-rules-admin-form', 'file' => 'theme.inc', 'path' => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1/theme', 'arguments' => array ('form' => NULL), 'type' => 'module', 'theme path' => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1', 'include files' => array (0 => './sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1/theme/theme.inc'), 'theme paths' => array (0 => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1/theme'), 'preprocess functions' => array (0 => 'template_preprocess', 1 => 'template_preprocess_drupal_tweaks_msg_rules_form')), 'drupal_tweaks_module_admin_modules' => array ('file' => 'theme.inc', 'path' => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1/theme', 'arguments' => array ('form' => NULL), 'type' => 'module', 'theme path' => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1', 'function' => 'theme_drupal_tweaks_module_admin_modules', 'include files' => array (0 => './sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1/theme/theme.inc'), 'theme paths' => array (0 => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1/theme'), 'preprocess functions' => array (0 => 'template_preprocess'))), $type = 'base_theme', $theme = 'zen', $path = 'sites/all/themes/zen' )
16	0.2348	1742328	_zen_theme( $existing = array ('status_messages_dt' => array ('arguments' => array ('display' => NULL), 'type' => 'module', 'theme path' => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1', 'function' => 'theme_status_messages_dt', 'include files' => array (), 'theme paths' => array (0 => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1'), 'preprocess functions' => array (0 => 'template_preprocess')), 'drupal_tweaks_msg_rules_form' => array ('template' => 'msg-rules-admin-form', 'file' => 'theme.inc', 'path' => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1/theme', 'arguments' => array ('form' => NULL), 'type' => 'module', 'theme path' => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1', 'include files' => array (0 => './sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1/theme/theme.inc'), 'theme paths' => array (0 => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1/theme'), 'preprocess functions' => array (0 => 'template_preprocess', 1 => 'template_preprocess_drupal_tweaks_msg_rules_form')), 'drupal_tweaks_module_admin_modules' => array ('file' => 'theme.inc', 'path' => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1/theme', 'arguments' => array ('form' => NULL), 'type' => 'module', 'theme path' => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1', 'function' => 'theme_drupal_tweaks_module_admin_modules', 'include files' => array (0 => './sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1/theme/theme.inc'), 'theme paths' => array (0 => 'sites/all/modules/bro/drupal_tweaks-DRUPAL-6--1/theme'), 'preprocess functions' => array (0 => 'template_preprocess'))), $type = 'base_theme', $theme = 'zen', $path = 'sites/all/themes/zen' )	../template.php:28
17	0.2458	1788192	array_merge ( array (0 => 'zen_show_blocks_discovery'), NULL )	../template.theme-registry.inc:74

    $existing['page']['preprocess functions'] = array_merge(array('zen_show_blocks_discovery'), $existing['page']['preprocess functions']);