All my pages result in 404 page not found or another error. Url rewriting (or "pretty urls") might be not enabled or configured properly, check the following if you are facing 404 page not found:
.htaccess file from codecanyon zip did not get copied over properly to your server.
Apache mod_rewrite module is disabled on your server, you will most likely need to contact your hosting support regarding this, unless you have access to server configuration.
Overrides via .htaccess file are not allowed, you will most likely need to contact your hosting support for this as well.
You are using nginx or windows server instead of apache. You can find nginx rules here, and windows server has a module that allows you to import .htaccess file or there are several online services that can convert .htaccess file to web.config