Server closed the connection unexpectedly

I’m getting these errors periodically:

PGError: server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
: SELECT * FROM works ORDER BY added desc LIMIT 10

/usr/lib/ruby/gems/1.8/gems/activerecord-1.13.2/lib/active_record/connection_adapters/abstract_adapter.rb:88:in
log' /usr/lib/ruby/gems/1.8/gems/activerecord-1.13.2/lib/active_record/connection_adapters/postgresql_adapter.rb:137:inexecute’
/usr/lib/ruby/gems/1.8/gems/activerecord-1.13.2/lib/active_record/connection_adapters/postgresql_adapter.rb:351:in
select' /usr/lib/ruby/gems/1.8/gems/activerecord-1.13.2/lib/active_record/connection_adapters/postgresql_adapter.rb:118:inselect_all’
/usr/lib/ruby/gems/1.8/gems/activerecord-1.13.2/lib/active_record/base.rb:431:in
find_by_sql' /usr/lib/ruby/gems/1.8/gems/activerecord-1.13.2/lib/active_record/base.rb:395:infind’
./config/…/app/controllers/works_controller.rb:4:in `index’
/usr/bin/mongrel_rails:18

Most of the time the page loads fine. Any idea what the problem is?
There’s nothing in postgresql’s log.

Joe