It sounds to me like you are confusing registration with hosting. There is no "propagation" at all involved with registering a domain. There is, however, a period of time during which DNS is updated across the web after a change of nameservers, or DNS record changes on a nameserver. I suspect that is what you mean when you say "propagation", and there here is more on that here:
Registering a domain at DreamHost does not make it available on the web automatically. You have to either "Add a Domain" in the "Domains -> Manage Domains" section of the web account control panel, or set the nameservers to some other host where the content is hosted, for the domain to be reachable via DNS.
If you have not done that, and DreamHost's nameservers are being used (which is the case by default with DreamHost registered domain), then your domain will never "propagate" and be reachable on the web!
--DreamHost Tech Support