Problems with Permissions

I Think this is maybe not a problem of the plugin self. but the plugin is the one thing, that throw errors because this:

Warning: copy(/www/htdocs/w01397c8/public/wp-content/advanced-cache.php): failed to open stream: Permission denied in /www/htdocs/w01397c8/public/wp-content/plugins/hummingbird-performance/core/modules/class-module-page-cache.php on line 215

Warning: Cannot modify header information – headers already sent by (output started at /www/htdocs/w01397c8/public/wp-content/plugins/hummingbird-performance/core/modules/class-module-page-cache.php:215) in /www/htdocs/w01397c8/public/wp-admin/includes/misc.php on line 1116

i tryed couple of things, like adding the ftp data to the wp-config.php. But nothing solve this problem.

Maybe i can find here help to solve this? Or its maybe a problem of the Plugin self?

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