HTTP ERROR 500 QuickSubmitPlugin

Hello, @asmecher and all the teams,
I am now using OJS, everything is working fine.
I just installed the quick submit plugin manually via cpanel. The plugin has been detected in ojs, but when I click on it, HTTP ERROR 500 appears.
Screen Shot 2020-12-27 at 04.45.08
Thanks to anyone who can give me a hand to solve the problem

And this is additional information we got from error log

Please help me to solve this problem

PHP Warning:  filemtime(): stat failed for lib/pkp/templates/layouts/backend.tpl in /home/asceeorg/public_html/pubs/lib/pkp/classes/template/ on line 51
PHP Fatal error:  Uncaught  --> Smarty: Unable to load template 'app:layouts/backend.tpl' in 'plugins-plugins-importexport-quickSubmit-master-importexport-quickSubmit-master:index.tpl' <-- thrown in /home/asceeorg/public_html/pubs/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_internal_template.php on line 195