Most likely one or both of the servers do not explicitly allow site to site transfers. For the FTP server software used above in your log this is the standard configuration by design. If these are dedicated servers and you have root access to change the FTP server configuration it is very simple to change the setting to allow site to site transfers.
ProFTPd -
http://www.proftpd.org/docs/howto/FXP.html
NcFTPd -
http://www.ncftp.com/ncftpd/doc/conf...nnections.html