HELP – messed up the wp-includes rewrite.php file

So I’m using ipage with the domain cuperu.org and I had a friend build me another website using wordpress and the subdomain cuperu.org/newsite.

I’m not very IT smart and was attempting to make this new website viewable directly at cuperu.org. In the process of trying to figure out how to switch the subdomain to be the main domain, i was told I need to fix permalinks on my wordpress. I found this site https://kevinworthington.com/how-to-fix-permalinks-in-wordpress-when-all-else-fails/

I then tried to save the rewrite.php file and upload it to the ipage file manager under newsite folder, wp-incudes folder. I think I may have erased something because now I’m getting this message when I try and visit the URL cuperu.org/newsite

Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, ‘_wp_filter_taxonomy_base’ was given in /hermes/bosweb/web278/b2780/ipg.cuperuorg/newsite/wp-includes/plugin.php on line 170

Fatal error: Call to undefined function add_permastruct() in /hermes/bosweb/web278/b2780/ipg.cuperuorg/newsite/wp-includes/taxonomy.php on line 346

When I delete the rewrite.php file thinking that it is causing something bad. I get a different error:

Warning: require(/hermes/bosweb/web278/b2780/ipg.cuperuorg/newsite/wp-includes/rewrite.php) [function.require]: failed to open stream: No such file or directory in /hermes/bosweb/web278/b2780/ipg.cuperuorg/newsite/wp-settings.php on line 129

Fatal error: require() [function.require]: Failed opening required ‘/hermes/bosweb/web278/b2780/ipg.cuperuorg/newsite/wp-includes/rewrite.php’ (include_path=’.:/usr/local/lib/php-5.2.17/lib/php’) in /hermes/bosweb/web278/b2780/ipg.cuperuorg/newsite/wp-settings.php on line 129

Again, I don’t really know what I’m doing and I really would like to get my “under construction” website up and running and switch it over to the main domain. If anyone out there knows what’s going on, I would really appreciate your help!!!
Thank you!
Igor