having problem with setting up subdomains

[Lila]

Every time I go into Add Subdomain in my control panel and write in the name of the subdomain I want to create I get an error like this: could not be modified because it does not resolve to a valid ip address. Ignore any messages of success this can only result in failure! Can anyone tell me how to setup a subdomain without getting errors?

[petesmc]

Have you done what you wre told and asked HostRocket via a trouble ticket to set up subdomains for you???

Peter