I checked the file dyndns.log file and it has only one line:
nohost
Do you know which client is being used? I have been having some other troubles as well. I had a linksys router before the e-smith box and the problems started after removing the router. I also noticed that the port forwarding quit working at the same time. I went into the server-manager and removed the port forwarding and then readded it, which made it work. I downloaded the port forwarding rpm from one of the how-tos.
Thanks
Trampas