Help! Suddenly cannot connect

Help! I have been using SmartFTP for quite awhile now, with no problems. As of last night, I cannot connect...I keep getting this message:
SmartFTP v1.1.985.6
Resolving host name yourserver.com...
No such host is known.
Active Help Link: https://www.smartftp.com/support/kb/83
Connection closed.
I therefore purchased a licensed copy, installed it, and still I get the same message. I've disabled all the firewalls I can find...I have McAffee and WindowsXP...have disabled BOTH at this point...any suggestions would be greatly appreciated!!

Thanks,
Kim

Problem solved through email.

-Mat