I have tried to set up dd client with my dyndns account, but I get the error "Empty host list".
What can be wrong? Have I done something wrong in the setup on dyndns, or is it something with the ddclient I don't grasp?
You're missing a part in your configuration. Could you post your config on http://ddclient.pastebin.ca/ with your password removed. Post the location here. It should contain something like:
The error "empty host list" means it could not decode the line with the hostnames.