4.7-5.1: Problems with encoding but my tables are UTF-8

Hi, I'm getting this problem after I make a comment or create some content or deleting content or doing something:

Warning: pg_query() [function.pg-query]: Query failed: ERROR: secuencia de bytes no v�lida para codificaci�n �UTF8�: 0xe16d65 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". in /home/www/drupal/includes/database.pgsql.inc on line 125

Warning: ERROR: secuencia de bytes no v�lida para codificaci�n �UTF8�: 0xe16d65 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". query: INSERT INTO watchdog (uid, type, message, severity, link, location, referer, hostname, timestamp) VALUES (1, 'php', '<em>pg_query() [&lt;a href=&#039;function.pg-query&#039;&gt;function.pg-query&lt;/a&gt;]: Query failed: ERROR: par�metro de configuraci�n no reconocido: �tables�</em> en la línea <em>125</em> del archivo <em>/home/www/drupal/includes/database.pgsql.inc</em>.', 2, '', 'http://ghostbar.ath.cx/admin/settings/db_maintenance', 'http://ghostbar.ath.cx/admin', '190.37.73.254', 1170596086) in /home/www/drupal/includes/database.pgsql.inc on line 144

Warning: pg_query() [function.pg-query]: Query failed: ERROR: secuencia de bytes no v�lida para codificaci�n �UTF8�: 0xe16c69 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". in /home/www/drupal/includes/database.pgsql.inc on line 125

Warning: ERROR: secuencia de bytes no v�lida para codificaci�n �UTF8�: 0xe16c69 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". query: INSERT INTO watchdog (uid, type, message, severity, link, location, referer, hostname, timestamp) VALUES (1, 'php', '<em>ERROR: secuencia de bytes no v�lida para codificaci�n �UTF8�: 0xe16d65 HINT: This error can also happen if the byte sequence does not match the encoding expected by the server, which is controlled by &amp;quot;client_encoding&amp;quot;. query: SHOW TABLES</em> en la línea <em>144</em> del archivo <em>/home/www/drupal/includes/database.pgsql.inc</em>.', 2, '', 'http://ghostbar.ath.cx/admin/settings/db_maintenance', 'http://ghostbar.ath.cx/admin', '190.37.73.254', 1170596086) in /home/www/drupal/includes/database.pgsql.inc on line 144

I can't understand why, update.php doesn't report any kind of problems. I'm using PostgreSQL