No connection could be made because the target computer actively refused it. This usually results from trying to connect to a service that is inactive on the foreign host.
Either you went to the wrong host, or the server application you're trying to contact isn't executing. Check the destination address you are using. If you used a hostname, did it resolve to the correct address? If the hostname resolution uses a local host table, it's possible you resolved to an old obsolete address. It's also possible that the local services file has an incorrect port number (although it's unlikely). You can verify that the remote system is rejecting your connection attempt by checking the network statistics locally. Check that your network system (Winsock implementation) has a utility that shows network statistics. You could use this to verify that you're receiving TCP resets or ICMP Port Unreachable packets each time you attempt to connect.