Usually this error occurs when you try to upload large files. You can check for the following at your local machine:
1. Try enabling "passive mode" in your FTP client.
2. Check your personal firewall/security settings (programs like Black ICE Defender, Zone Alarm, Norton Anti-Virus) to make sure that they are configured to allow FTP access. Try turning these programs completely off and retry FTP.
3. Check for any timeout settings in your local FTP client and try increasing this.
4. If you continue to have trouble, the time out via the FTP is most likely because of one or more dropped packets at your ISP or at any of the intermediate routers. When you connect to our server, you are usually going through 14-20 other routers before it gets to our destination. If any one of them lose a packet it can cause problems with FTP. One way to get around this is to have a constant PING open - this keeps the connection through the different servers alive.
In Windows Machine :
open a DOS window on your computer and type the following, it will keep a ping open:
ping -t domainname.com
In Linux Machine, use the command line below:
**Replace "domainname.com" with your domain name. Then once your upload has completed, press Control-C to cancel the ping.