Point PostgreSQL on Ubuntu to a new datadir
You can't just copy base from the old cluster to the new one. It doesn't work like that. You'll be missing the transaction logs, transaction commit statuses, global catalogs, and all the other components that make those databases make any sense.

Instead, pg_createcluster in the new location, then replace the entire data directory with the one from your old system. That's the directory with base, pg_xlog, global, etc in it.