This error generally occurs when port 21 is blocked on your computer. The port could be blocked by a firewall or a proxy server that has not been configured properly. Generally you'll see a log like this:
STATUS:> Connecting to server xxx.xxx.x.xx (ip= xxx.xxx.x.xx)...
ERROR:> Can't connect to remote server. Socket error = #2000.
ERROR:> Timeout (60000ms).
STATUS:> Waiting 30 seconds......
To avoid this error, open port 21 to inbound and outbound traffic. Most often a firewall (such as those from MacAfee, Norton or the built-in Windows XP firewall) will be blocking inbound or outbound TCP traffic on port 21.