Thread:Project:Support desk/Error loading CSS/reply

Without a URL to the wiki and without the exact MediaWiki version it's only guessing.

But my crystal ball says that calls to load.php are not working properly in your installation. This problem is usually caused by wrong or missing rewrite rules in .htaccess. Requests to the file load.php must be allowed - and not changed by mod_rewrite. Calling the file should not bring up a wiki page, but you must be able to access this file.