public function findError()
    {
        $requiredEnvironmentError = $this->ensureRequiredEnvironment();
        if ($requiredEnvironmentError !== null) {
            return $this->setErrorTitle($requiredEnvironmentError, 'Environment requirements not fulfilled');
        }

        $filePermissionsError = $this->checkFilePermissions();
        if ($filePermissionsError !== null) {
            return $this->setErrorTitle($filePermissionsError, 'Error with file system permissions');
        }

        return null;
    }