error while making ai covers

so after i select a model and the file and click sumbit it gives me this error on the process page

Warning: Undefined variable $audioFiles in /var/www/easyaivoice.com/public_html/process.php on line 150

Fatal error: Uncaught TypeError: array_unique(): Argument #1 ($array) must be of type array, null given in /var/www/easyaivoice.com/public_html/process.php:150 Stack trace: #0 /var/www/easyaivoice.com/public_html/process.php(150): array_unique() #1 {main} thrown in /var/www/easyaivoice.com/public_html/process.php on line 150