Our users have reported a bug where migrating a slave DB on postgres 8.4 results in this error:
ERROR: syntax error at or near “ORDER”
LINE 6: SELECT array_agg(artist_credit ORDER BY artist_credit AS…
If you are 8.4 please wait on your migration — we’re hoping to have a workaround ready today. If you need to get this fixed sooner, moving to postgres 9.x or importing the 2012-10-17 data dump would solve this problem.
Sorry for the troubles!
MetaBrainz Blog 