Error restoring backup

Hallo to all
I’m restoring the backup but when go to the installer.php page show following error, someone has idea of the problem?

Fatal error: Uncaught Error: Call to undefined function disk_free_space() in /NAS1/vhosts/LI13668/ildiariodeipiccoligeni.com/public_www/dup-installer/views/view.s1.base.php:77 Stack trace: #0 /NAS1/vhosts/LI13668/ildiariodeipiccoligeni.com/public_www/dup-installer/main.installer.php(373): require_once() #1 {main} thrown in /NAS1/vhosts/LI13668/ildiariodeipiccoligeni.com/public_www/dup-installer/views/view.s1.base.php on line 77

Fatal error: Uncaught Exception: [PHP ERR][FATAL] MSG:Uncaught Error: Call to undefined function disk_free_space() in /NAS1/vhosts/LI13668/ildiariodeipiccoligeni.com/public_www/dup-installer/views/view.s1.base.php:77 Stack trace: #0 /NAS1/vhosts/LI13668/ildiariodeipiccoligeni.com/public_www/dup-installer/main.installer.php(373): require_once() #1 {main} thrown [CODE:1|FILE:/NAS1/vhosts/LI13668/ildiariodeipiccoligeni.com/public_www/dup-installer/views/view.s1.base.php|LINE:77] in /NAS1/vhosts/LI13668/ildiariodeipiccoligeni.com/public_www/dup-installer/classes/class.logging.php:200 Stack trace: #0 /NAS1/vhosts/LI13668/ildiariodeipiccoligeni.com/public_www/dup-installer/classes/class.logging.php(335): DUPX_Log::error() #1 /NAS1/vhosts/LI13668/ildiariodeipiccoligeni.com/public_www/dup-installer/classes/class.logging.php(449): DUPX_Handler::error() #2 [internal function]: DUPX_Handler::shutdown() #3 {main} thrown in /NAS1/vhosts/LI13668/ildiariodeipiccoligeni.com/public_www/dup-installer/classes/class.logging.php on line 200