The table admin (this is not a system table, its for administrative borders) was incorrectly setup in the new postgres. Please change the ownership of that table to osmimporter (just like all other tables), and a few indexes are missing:

• ALTER TABLE admin OWNER TO osmimporter;
• CREATE INDEX admin_way_idx ON admin USING gist (way);
• CREATE INDEX planet_osm_rels_parts ON planet_osm_rels USING gin (parts) WITH (fastupdate=off);

I tried to create the last index (since it belongs to the osmimporter), but the query simply hung there, with the waiting status set to "t". This might be due to the osmupdater still running (hanging).