Cannot login waiting to retry

I downloaded smart ftp a couple of days ago and it was great.Then today a cant login to anything. Get "Cannot login waiting to retry" and reference to the software being unregistered.
looked around the forums and found reference to the digital signature for SFTPMSI.exe being corrupt. So downloaded beta version SFTPNSI.exe and its all working again but interestingly the digital signature still shows an error.
I'm running it on win98
Seems a few people are having this problem. Is there a solution.

Many thanks


As said in other posts if your system is not able to verify the digital signature the problem is with your system or the configuration of it. Also using Windows 98 is not recommended at all.