ip not getting updated when cable modem changes

I have not been able to find anything on this and now I cannot get to my Linux systems remotely.

I have a linksys router and a cable modem at one location. I have a belkin router and cable modem at the 2nd location.

I registered with http://dyndns.org for 2 unique accounts (one for each location). I logged into each router on the local network and activated the dyndns options on the individual routers and entered my ID and passwd into the appropriate fields. They connected fine for a few days (about a week)or so I thought as the redirect to the url worked fine. The other day the belkin site went offline. I figured it was just something minor.

Now last night I unplugged my cable modem to move it so I am guessing it got a new IP. I did not check it when I was there but my cable modem worked fine. So I am guessing the request to update my dyndns info did not go out.

Is there some step I missed? I read their online docs and several google hits but they were back from 2003 and talked about a problem that I am sure was fixed by now. I dont know the model of the router off the top of my head but they are G and wireless. I am guessing there is nothing I can do remotely from the http://dnydns.org account to force an update to my account. If there is any specific info you need about my routers I can get it after work.

From what I read it was

1. set up http://dyndns.org account and register a domain name such as my http://house.dyndns.org
2. Login to router and turn on the dyndns setting and enter my uid/passwd
3. optional: reset router and cable modem to be sure it works.

Do I need to run some client on my pc or my Linux box? I dont really use windows any more. So if there is a Linux client i need I could do that. I am running CentOS5.5. My understanding is that you dont need that with the newer routers. Thats what the build in sw is for.

Did I miss something?
Thanx

CJ