404 error not found when trying to add new fields to new editor

Every time I try and create a new field, doesn't matter the field type I receive a pop up error message saying 404 error not found. We recently just launched this website from our testing server and everything works fine on that server. I am able to add as many fields as needed without any problems. However this problem only occurs on the current live site server. If I happen to rename the htaccess file i then receive a 403 forbidden error when trying to create new fields. Is there a way to fix this so that i can continue to add fields into the cms?