You should not be seeing a 404 error or 500 errors and should either be seeing a 200 OK or 403 Forbidden error. If you want me to figure out what is going on on each of these sites then I need FTP access to each of these sites. Send the FTP login information in this format below to this email address: info at ait-pro dot com.
I assume this is FTP and not sftp.
Hostname:
Username:
password: