OK. I solved the problem by myself. I had to rename the .htaccess files in folders modules and themes. I think you can close the topic, unless you see some other errors on my site.
Hi! I have just installed prestashop 1.6.0.9 on my site : http://x-army.pl/ As you can see , the site looks like some basic html list. I have no idea what could possibly cause that error. Can anyone help me ,please?