I have a website that has an index.php, a few simple .html pages and one .php page (contact form) as well as a .htaccess file. On my website I have buttons that point to the
You might be including it with a relative path? When your'e using ./ you are trying to include something from the new (non excistent?) /welcome dir.
Try to include your stuff trough the complete path, or use some sort of variable that tells you the real basepath.