Fatal Error on plugin activation

Hi.

Today I try to install latest version of plugin in my website.
Whem I click on ACTIVATE, result is this:

Fatal error: Uncaught TypeError: fwrite(): Argument #1 ($stream) must be of type resource, bool given in /var/www/XXXXXXXXXX/wp-content/plugins/duplicator/classes/utilities/class.u.php:644 
Stack trace: 
#0 /var/www/XXXXXXXXXX/wp-content/plugins/duplicator/classes/utilities/class.u.php(644): fwrite() 
#1 /var/www/XXXXXXXXXX/wp-content/plugins/duplicator/classes/class.plugin.upgrade.php(65): DUP_Util::setupBackupDirHtaccess() 
#2 /var/www/XXXXXXXXXX/wp-content/plugins/duplicator/classes/class.plugin.upgrade.php(46): DUP_LITE_Plugin_Upgrade::secureLocalStorageDirectory() 
#3 /var/www/XXXXXXXXXX/wp-content/plugins/duplicator/classes/class.plugin.upgrade.php(19): DUP_LITE_Plugin_Upgrade::updateInstallation() 
#4 /var/www/XXXXXXXXXX/wp-includes/class-wp-hook.php(307): DUP_LITE_Plugin_Upgrade::onActivationAction() 
#5 /var/www/XXXXXXXXXX/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters() 
#6 /var/www/XXXXXXXXXX/wp-includes/plugin.php(476): WP_Hook->do_action() 
#7 /var/www/XXXXXXXXXX/wp-admin/plugins.php(194): do_action() 
#8 {main} thrown in /var/www/XXXXXXXXXX/wp-content/plugins/duplicator/classes/utilities/class.u.php on line 644

Someone can help me?
Thanks.
Davide.