This post is old, but I see it shows not answered. I was experiancing the same error after upgrading to 3.2.1 from 3.0 and this is what worked for me.
Symptoms
\Device\HTTP Class device for website did not show an IP on it's overview page. Attempting to reset the IP address failed.
Website runs on a load balanced cluster of 2 IIS web servers. Both servers where also monitored by Zenoss as class \Device\Server\Windows. Server 2 showed the cluster IP as attached to one it's interfaces
To resolve the issue,
1. I installed the ZenPack Virtual IP docs/DOC-5800
2. On each of the servers I set the load balance IP (that the website responded to) to be ignored, following the instructs with the Zen Pack.
3. Modled each server and verfied the shared IP no longer showed
4. Modled the website device and verified it showed an IP.
5. Clear all events for the HTTP device and wait.
I.O.W.
Before following steps above, zenoss saw things as
Server1 IP 192.168.1.2
Server2 IP 192,169.1.3, 192.168.1.1
www.website.com IP none
After steps above, zenoss saw things as
Server1 IP 192.168.1.2
Server2 IP 192,169.1.3,
www.website.com IP 192.168.1.1
I imagine this would be the same if there was only 1 web server since,at least in 3.2.1, Zenoss is very strict on IP addresses not being used by multiple devices.
