That does appear with the exact same spelling you on "manage domains" page in the panel right? Does the "web hosting" column on that page say "Fully hosted"?
If both of those are affirmative then you should open a ticket with support via the panel because that sub-domain is not showing up in DNS at all. https://panel.dreamhost.com/index.cgi?tree=support.msg&
$ nslookup whywaitforsomethingelse.dreamhosters.com
** server can't find whywaitforsomethingelse.dreamhosters.com: NXDOMAIN