The 10053 error happens when PingPlotter or MultiPing is having problems talking to the SMTP server (this is a standard Winsock error). Specifically, this happens when a connection is properly initiated, but then something abruptly ends the conversation.

Usually, this is because of some kind of firewall running between you and the SMTP server (maybe on your local machine, or someplace between you and the SMTP server). It can also be because of a SMTP server problem of some kind.

If you're running McAfee Anti-Virus 8.0i, make sure PingPlotter (pingplotter.exe) or MultiPing (multiping.exe) is an allowed program.

If you're using any kind of SMTP proxy (Norton Antivirus is one of these that proxies SMTP to make sure you don't send out any viruses), then check to see if you can work around that somehow.

Also, check to see if one of your SMTP servers will allow incoming connections on a non-standard port and try using that port instead of the standard port 25.