The following bug has been logged on the website:
Bug reference: 7873
Logged by: Dave Rolsky
Email address: autarch@urth.org
PostgreSQL version: 9.2.3
Operating system: Linux
Description: =
When you pass the --clean option to pg_restore it tries to drop tables
without checking if they exist. This results in lots of error output. If
you're running pg_restore via an automated process it's very hard to
distinguish between these "ok" errors and real errors.
It should be using "DROP TABLE IF EXISTS" and the equivalent for
constraints.