Thought for the moment...
I had the same problem with messages:
"... dyndns.org: Unknown response . Status was 0"
As a desperate measure I changed my dyndns password. Originally I had a password which included the "@" character. Perhaps a bit ambitious, I now concede, although there were no problems logging on via their web site, etc. With the new password (more "conventional" characters) there is no more problem with e-smith updates.
If I knew anything about the relevant scripting language for changing the e-smith code, I would offer a fix. Something which allowed for "escape" characters in password strings. But I don't, so I haven't...
Hope this might offer some clues, anyway.
Cheers,
Dave