Problem to upload styles in a theme

Hi, i’m trying to upload a file with .css styles and it’s not working for me. When i check in the apache error log, i get the following error

PHP Fatal error:  Uncaught Error: Call to undefined method PrivateFileManager::deleteByPath() in /var/www/ojs/lib/pkp/classes/file/TemporaryFileManager.inc.php:53\nStack trace:\n#0 /var/www/ojs/lib/pkp/controllers/tab/settings/form/SettingsFileUploadForm.inc.php(111): TemporaryFileManager->deleteById('4', '1')\n#1 /var/www/ojs/lib/pkp/controllers/tab/settings/appearance/form/NewContextCssFileForm.inc.php(75): SettingsFileUploadForm->removeTemporaryFile(Object(Request))\n#2 /var/www/ojs/controllers/tab/settings/WebsiteSettingsTabHandler.inc.php(108): NewContextCssFileForm->execute()\n#3 /var/www/ojs/lib/pkp/classes/core/PKPRouter.inc.php(390): WebsiteSettingsTabHandler->saveFile(Array, Object(Request))\n#4 /var/www/ojs/lib/pkp/classes/core/PKPComponentRouter.inc.php(257): PKPRouter->_authorizeInitializeAndCallRequest(Array, Object(Request), Array)\n#5 /var/www/ojs/lib/pkp/classes/core/Dispatcher.inc.php(134): PKPComponentRouter->route(Object(Request))\n#6 /var/www/ojs/lib/pkp/classes/core/PKPApplication.inc.php(252): Dispatcher->dispat in /var/www/ojs/lib/pkp/classes/file/TemporaryFileManager.inc.php on line 53, referer: https://revistasdesa2018.ort.edu.uy/?journal=anales-de-investigacion-en-arquitectura&page=admin&op=contexts&openWizard=1