uploaded new version - not connecting!

I've just upgraded to the new version, but now keep getting this error when I try to connect. ...

Unable to resolve host name

This error means that the hostname you are trying to connect to cannot be resolved to an IP address. (Hostnames are resolved to IP addresses by a DNS (Domain Name Server).

Please see what you have put in the Address field. You will need the valid hostname of an ftp server or a valid IP address.

If connecting through the favorites. Only the name or address of the FTP server belongs in the host section. You should not include URL or path information in this field.

If you have verified that the hostname is correct, there may be a problem with your DNS server (or with your ISP's DNS server if you are a standalone user). It may be unable to resolve hostnames to IP addresses.
At this point it would be a good idea to contact your ISP about the problem, or network administrator.

I have to point out at this stage that I'm close to useless; but also had used the old version with no problems, and for so long that I can't remember how to solve probs when they arise!!

If anyone can help with this (prob v.v. easy) issue, I'd be grateful!

li

The problem is caused by a software firewall / antivirus software installed on your computer. Our technical support team can offer you a solution after you have purchased a license.

Regards,
SmartFTP

ok thanks... but is this due to my antivirus software/firewall changing - or differences in the new version?

(I ask as my antivirus has been playing up anyway, so wondering if that could be it)