The domain is in fact registered at dreamhost. The nameservers are in fact pointed to behost.com.
However, the only thing you can currently accomplish via the dreamhost panel is to change the nameservers. Since the nameservers are pointed elsewhere you can't in fact create a redirect for the domain using the dreamhost panel.
If you did something in the dreamhost panel to create the redirect it can't work, because the nameservers are pointed to behost.com. To make a redirect in the dreamhsot panel work you would need to change nameservers of the domain to ns1.dreamhost.com, ns2.dreamhost.com, ns3.dreamhost.com, or instead you could perhaps create the redirect at behost.com
Standard warning: All of the changes being discussed here affect DNS. DNS changes do not occur instantly. Allow anywhere from a few minutes to 72 hours. (most occur in less than 12 hours, with the average in the 3-6 hour range, however your mileage may vary)