No conection

Hello to everyone:
I can not conect to any ftp server using this or any other soft. SmattFTP give me this message:
[16:10:53] SmartFTP v2.0.996.12
[16:10:54] Resolving host name ""
[16:10:54] Connecting to Port: 21
[16:10:54] Connected to
[16:11:15] An established connection was aborted by the software in your host machine.
[16:11:15] Server closed connection
[16:11:15] Cannot login waiting to retry (60s)...
I can see and download the content of ftp servers usin IE 7.0
My connection is trough a proxy server and don't know how to setting the proxy configuration in SmartFTP
Can anybody help me???