Can't get SmartFTP to launch

Hi. Not sure what to do; I've been getting the expiration box and then nothing happens when I click on 'ok' - used to be just a warning. So, I downloaded and installed the newest version over what I have.. same result - app won't launch; then I removed the version of smartftp I had and then ran the install for the new version again.. same problem. Please help.
Thanks.
Lauri