Fatal error: Uncaught TypeError: PKP\plugins\PluginRegistry::_deprecatedInstantiatePlugin(): Return value must be of type ?PKP\plugins\Plugin, int returned in /home/k0651780/ejournal.stiejb.ac.id/lib/pkp/classes/plugins/PluginRegistry.php:259 Stack trace: #0 /home/k0651780/ejournal.stiejb.ac.id/lib/pkp/classes/plugins/PluginRegistry.php(193): PKP\plugins\PluginRegistry::_deprecatedInstantiatePlugin('themes', 'default') #1 /home/k0651780/ejournal.stiejb.ac.id/lib/pkp/classes/plugins/PluginRegistry.php(219): PKP\plugins\PluginRegistry::_instantiatePlugin('themes', 'default', 'DefaultThemePlu...') #2 /home/k0651780/ejournal.stiejb.ac.id/lib/pkp/classes/plugins/PluginRegistry.php(112): PKP\plugins\PluginRegistry::_loadFromDatabase('themes', NULL) #3 /home/k0651780/ejournal.stiejb.ac.id/lib/pkp/classes/template/PKPTemplateManager.php(1440): PKP\plugins\PluginRegistry::loadCategory('themes', true) #4 /home/k0651780/ejournal.stiejb.ac.id/lib/pkp/classes/plugins/Plugin.php(403): PKP\template\PKPTemplateManager::getManager(Object(APP\core\Request)) #5 /home/k0651780/ejournal.stiejb.ac.id/lib/pkp/classes/plugins/Plugin.php(137): PKP\plugins\Plugin->_registerTemplateResource() #6 /home/k0651780/ejournal.stiejb.ac.id/lib/pkp/classes/plugins/LazyLoadPlugin.php(34): PKP\plugins\Plugin->register('generic', 'plugins/generic...', NULL) #7 /home/k0651780/ejournal.stiejb.ac.id/plugins/generic/customBlockManager/CustomBlockManagerPlugin.php(54): PKP\plugins\LazyLoadPlugin->register('generic', 'plugins/generic...', NULL) #8 /home/k0651780/ejournal.stiejb.ac.id/lib/pkp/classes/plugins/PluginRegistry.php(76): APP\plugins\generic\customBlockManager\CustomBlockManagerPlugin->register('generic', 'plugins/generic...', NULL) #9 /home/k0651780/ejournal.stiejb.ac.id/lib/pkp/classes/plugins/PluginRegistry.php(121): PKP\plugins\PluginRegistry::register('generic', Object(APP\plugins\generic\customBlockManager\CustomBlockManagerPlugin), 'plugins/generic...', NULL) #10 [internal function]: PKP\plugins\PluginRegistry::PKP\plugins\{closure}(Object(APP\plugins\generic\customBlockManager\CustomBlockManagerPlugin), 'plugins/generic...') #11 /home/k0651780/ejournal.stiejb.ac.id/lib/pkp/classes/plugins/PluginRegistry.php(121): array_walk_recursive(Array, Object(Closure)) #12 /home/k0651780/ejournal.stiejb.ac.id/lib/pkp/classes/core/Dispatcher.php(155): PKP\plugins\PluginRegistry::loadCategory('generic', true) #13 /home/k0651780/ejournal.stiejb.ac.id/lib/pkp/classes/core/PKPApplication.php(395): PKP\core\Dispatcher->dispatch(Object(APP\core\Request)) #14 /home/k0651780/ejournal.stiejb.ac.id/index.php(21): PKP\core\PKPApplication->execute() #15 {main} thrown in /home/k0651780/ejournal.stiejb.ac.id/lib/pkp/classes/plugins/PluginRegistry.php on line 259