553 requested action not taken

[lame newbie]

553 requested action not taken. What does this mean and how do I prevent it. I've established a connection with my networked pcs. My main pc won't send data to the other pc.
WinSock 2.0 -- OpenSSL 0.9.8b 04 May 2006

[R] Connected to xbox
[R] 220 Please enter your login name now.
[R] USER xbox
[R] 331 Password required for xbox.
[R] PASS (hidden)
[R] 230 User xbox logged in , proceed.
[R] SYST
[R] 215 UNIX Type: L8
[R] FEAT
[R] 502 feat is not implemented.
[R] REST 100
[R] 502 rest is not implemented.
[R] This site may not allow file resuming
[R] PWD
[R] 257 "/" is current directory
[R] TYPE A
[R] 200 Type set to ASCII.
[R] PASV
[R] 502 pasv is not implemented.
[R] Listening on PORT: 2128, Waiting for connection.
[R] PORT 192,168,0,100,8,80
[R] 200 Port command ok.
[R] LIST -al
[R] 150 Opening ASCII data connection for ls /.
[R] 226 Transfer finished successfully. Data connection closed.
[R] List Complete: 424 bytes in 5.45 seconds (0.1 KB/s)
[R] MKD / Downloads
[R] 553 Requested action not taken.
[R] CWD / Downloads
[R] 553 Requested action not taken. / Downloads/
Transfer queue completed
[R] MKD / Downloads
[R] 553 Requested action not taken.
[R] CWD / Downloads
[R] 553 Requested action not taken. /Downloads/
Transfer queue completed
[R] CWD G
[R] Connection lost: xbox
[R] Connecting to xbox -> IP=192.168.0.101 PORT=21
[R] Connected to xbox
[R] 220 Please enter your login name now.
[R] USER xbox
[R] 331 Password required for xbox.
[R] PASS (hidden)
[R] 230 User xbox logged in , proceed.
[R] SYST
[R] 215 UNIX Type: L8
[R] FEAT
[R] 502 feat is not implemented.
[R] REST 100
[R] 502 rest is not implemented.
[R] This site may not allow file resuming
[R] CWD /
[R] 250 "/" is current directory.
[R] PWD
[R] 257 "/" is current directory
[R] CWD G
[R] 250 "/G/" is current directory.
[R] PWD
[R] 257 "/G/" is current directory
[R] TYPE A
[R] 200 Type set to ASCII.
[R] PASV
[R] 502 pasv is not implemented.
[R] Listening on PORT: 2181, Waiting for connection.
[R] PORT 192,168,0,100,8,133
[R] 200 Port command ok.
[R] LIST -al
[R] 150 Opening ASCII data connection for ls /G/.
[R] 226 free disk space under this directory : 748.059.789.208
[R] List Complete: 54 bytes in 5.38 seconds (0.0 KB/s)
[R] MKD / Downloads
[R] 553 Requested action not taken.
[R] CWD / Downloads
[R] 553 Requested action not taken. / Downloads/
[R] MKD / Downloads
[R] 553 Requested action not taken.
[R] CWD / Downloads
[R] 553 Requested action not taken. / Downloads/
[R] MKD /B Downloads
[R] 553 Requested action not taken.
[R] CWD / Downloads
[R] 553 Requested action not taken. / Downloads/
Transfer queue completed

What does all this mean? Any clues in the log to help me with. Thanks in advance.