problem with open_id_authentication_plugin and PostgreSQL 8.2

I'm using open_id_authentication_plugin ( http://svn.rubyonrails.org/rails/plugins/open_id_authentication @ 7263 ) and it works perfectly with MySQL. If I switch to PostgreSQL 8.2 (on debian lenny) with a database with UTF8 encoding, I get the following exception:

PGError: ERROR: invalid byte sequence for encoding "UTF8": 0xe0ab03 HINT: This error can also happen if the byte sequence does not match the encoding expected by the server, which is controlled by "client_encoding". : INSERT INTO open_id_authentication_associations ("handle", "server_url", "lifetime", "assoc_type", "issued", "secret") VALUES(E'{HMAC-SHA1}{473ec62e}{ye1zmQ==}', E'http://www.myopenid.com/ server', 1209600, E'HMAC-SHA1', 1195296303, E'��nRIʸ�lUYE��S,')

RAILS_ROOT: /home/pic/pg Application Trace | Framework Trace | Full Trace

vendor/rails/activerecord/lib/active_record/connection_adapters/ abstract_adapter.rb:150:in `log' vendor/rails/activerecord/lib/active_record/connection_adapters/ postgresql_adapter.rb:404:in `execute' vendor/rails/activerecord/lib/active_record/connection_adapters/ abstract/database_statements.rb:156:in `insert_sql' vendor/rails/activerecord/lib/active_record/connection_adapters/ abstract/database_statements.rb:44:in `insert_without_query_dirty' vendor/rails/activerecord/lib/active_record/connection_adapters/ abstract/query_cache.rb:19:in `insert' vendor/rails/activerecord/lib/active_record/connection_adapters/ postgresql_adapter.rb:387:in `insert' vendor/rails/activerecord/lib/active_record/base.rb:2056:in `create_without_callbacks' vendor/rails/activerecord/lib/active_record/callbacks.rb:226:in `create_without_timestamps' vendor/rails/activerecord/lib/active_record/timestamp.rb:29:in `create' vendor/rails/activerecord/lib/active_record/base.rb:2022:in `create_or_update_without_callbacks' vendor/rails/activerecord/lib/active_record/callbacks.rb:213:in `create_or_update' vendor/rails/activerecord/lib/active_record/base.rb:1774:in `save_without_validation' vendor/rails/activerecord/lib/active_record/validations.rb:891:in `save_without_transactions' vendor/rails/activerecord/lib/active_record/transactions.rb:118:in `save' vendor/rails/activerecord/lib/active_record/connection_adapters/ abstract/database_statements.rb:66:in `transaction' vendor/rails/activerecord/lib/active_record/transactions.rb:90:in `transaction' vendor/rails/activerecord/lib/active_record/transactions.rb:110:in `transaction' vendor/rails/activerecord/lib/active_record/transactions.rb:118:in `save' vendor/rails/activerecord/lib/active_record/transactions.rb:130:in `rollback_active_record_state!' vendor/rails/activerecord/lib/active_record/transactions.rb:118:in `save' vendor/rails/activerecord/lib/active_record/base.rb:470:in `create' vendor/plugins/open_id_authentication/lib/open_id_authentication/ db_store.rb:28:in `store_association' /home/pic/opt/ruby/gems_repository/gems/ruby-openid-1.1.4/lib/openid/ consumer.rb:681:in `associate' /home/pic/opt/ruby/gems_repository/gems/ruby-openid-1.1.4/lib/openid/ consumer.rb:633:in `get_association' /home/pic/opt/ruby/gems_repository/gems/ruby-openid-1.1.4/lib/openid/ consumer.rb:468:in `begin' /home/pic/opt/ruby/gems_repository/gems/ruby-openid-1.1.4/lib/openid/ consumer.rb:301:in `begin_without_discovery' /home/pic/opt/ruby/gems_repository/gems/ruby-openid-1.1.4/lib/openid/ consumer.rb:281:in `begin' vendor/plugins/open_id_authentication/lib/open_id_authentication.rb: 96:in `begin_open_id_authentication' vendor/plugins/open_id_authentication/lib/open_id_authentication.rb: 155:in `timeout_protection_from_identity_server' vendor/plugins/open_id_authentication/lib/open_id_authentication.rb: 96:in `begin_open_id_authentication' vendor/plugins/open_id_authentication/lib/open_id_authentication.rb: 88:in `authenticate_with_open_id' app/controllers/sessions_controller.rb:38:in `open_id_authentication' app/controllers/sessions_controller.rb:12:in `create' -e:2:in `load' -e:2

I'am running ruby 1.8.6 (2007-06-07 patchlevel 36) [i486-linux] and edge Rails. Any ideas?

Thanks, Nicola