Включите отладку в настройках системы Joomla и выложите сюда вывод.
На стандартном шаблоне тоже есть ошибка ?
Да на стандартном тоже .
Function Location
1() JROOT\libraries\src\Application\CMSApplication.php:370
2Joomla\CMS\Application\CMSApplication::getMenu() JROOT\libraries\src\Application\SiteApplication.php:275
3Joomla\CMS\Application\SiteApplication::getMenu() JROOT\administrator\components\com_jce\models\editor.php:653
4WFModelEditor->getSiteTemplates() JROOT\administrator\components\com_jce\models\editor.php:704
5WFModelEditor->getStyleSheets() JROOT\administrator\components\com_jce\models\editor.php:144
6WFModelEditor->buildEditor() JROOT\plugins\editors\jce\jce.php:66
7plgEditorJCE->onInit() JROOT\libraries\joomla\event\event.php:70
8JEvent->update() JROOT\libraries\src\Editor\Editor.php:254
9Joomla\CMS\Editor\Editor->initialise() JROOT\libraries\src\Editor\Editor.php:561
10Joomla\CMS\Editor\Editor->_loadEditor() JROOT\libraries\src\Editor\Editor.php:352
11Joomla\CMS\Editor\Editor->save() JROOT\libraries\src\Form\Field\EditorField.php:345
12Joomla\CMS\Form\Field\EditorField->save() JROOT\components\com_content\views\form\tmpl\edit.php:37
13include() JROOT\libraries\src\MVC\View\HtmlView.php:701
14Joomla\CMS\MVC\View\HtmlView->loadTemplate() JROOT\libraries\src\MVC\View\HtmlView.php:230
15Joomla\CMS\MVC\View\HtmlView->display() JROOT\components\com_content\views\form\view.html.php:133
16ContentViewForm->display() JROOT\libraries\src\MVC\Controller\BaseController.php:672
17Joomla\CMS\MVC\Controller\BaseController->display() JROOT\components\com_content\controller.php:118
18ContentController->display() JROOT\libraries\src\MVC\Controller\BaseController.php:710
19Joomla\CMS\MVC\Controller\BaseController->execute() JROOT\components\com_content\content.php:43
20require_once() JROOT\libraries\src\Component\ComponentHelper.php:402
21Joomla\CMS\Component\ComponentHelper::executeComponent()JROOT\libraries\src\Component\ComponentHelper.php:377
22Joomla\CMS\Component\ComponentHelper::renderComponent()JROOT\libraries\src\Application\SiteApplication.php:194
23 Joomla\CMS\Application\SiteApplication->dispatch() JROOT\libraries\src\Application\SiteApplication.php:233
24 Joomla\CMS\Application\SiteApplication->doExecute() JROOT\libraries\src\Application\CMSApplication.php:196
25 Joomla\CMS\Application\CMSApplication->execute() JROOT\index.php:49