I had the exact same problem, which I noticed was actually my fault. Instead of using dyndns.biz (which was the domain I actually created my hostname in dyndns, I was using the default, dyndns.org.
When I noticed this and changed to the correct domain I created, it worked.
PS. by the way, it makes sense that the error message “no host” indicates that there was no such host as mine in the domain dyndns.org. Ok, it should be a little bit more verbose 😉
Hope this helps you.