Can not connect to my server

I just installed SmartFTP and it will not connect to my server. It did once yesterday, and then I tried to change a file, and it just sat there. I had to uninstall the program, and then reinstall it. After that I could change the filename, but it still will only connect to one of my servers. I know that the other ones are functioning, but SmartFTP just sit's there and will not connect. I have no idea what to do.
Thank you

i'm also not able to connect..

this is what my log shows-
[11:53:01] SmartFTP v2.5.1006.5
[11:53:01] Resolving host name "tpa-bg.org"
[11:53:02] Connecting to 208.101.10.240 Port: 21
[11:53:23] No connection could be made because the target machine actively refused it.
[11:53:23] Client closed the connection.
[11:53:23] Cannot login waiting to retry (30s)...
[11:53:23] Active Help: https://www.smartftp.com/support/kb/58
[11:53:53] Continue to login attempt 2...

Hello ..

The website tpa-bg.org is working fine here. I think there is a problem with your system configuration. Try to run an antivirus software to check your system for viruses. Uninstall the software firewall you are using. Enable the Windows XP firewall and try again.

Regards,
SmartFTP