If you are getting the mysterious error:
[ERROR] InsufficientPrivilege: permission denied for schema errors
Then you can easily resolve this by running the following SQL:
GRANT USAGE ON SCHEMA <schema_name> TO <redshift_user>;
Another common error that often follows this, is:
[ERROR] InsufficientPrivilege: permission denied for relation <table>
Luckily, this too can be resolved by running the following SQL:
GRANT USAGE ON SCHEMA <schema_name> TO <redshift_user>;
GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA <schema_name> TO <redshift_user>;