Browser cache problems

Hi there,

i did some page speed tests on the internet and found out that my site has some loading issues. One of them could be sped up by using browser cache. When i try to enable the browser cache i get this error:

W3 Total Cache Error: Files and directories could not be automatically created to complete the installation.
Please execute commands manually View required changes
or use FTP form to allow W3 Total Cache make it automatically.

I know that i should be checking my rights in ftp but they are all set correctly to 755 and htacces to 644. If i check the required changes it comes up with this.
Execute next commands in a shell:

cp /home/xxx/domains/xxx.com/public_html/wp-content/plugins/w3-total-cache/wp-content/object-cache.php /home/xxx/domains/xxx.com/public_html/wp-content/object-cache.php

I would like some help here 🙂

Thanks for your time,
Sjoerd