Error when submitting form

I get the following error when submitting the contact form as an anonymous user:

* warning: pg_query() [function.pg-query]: Query failed: ERROR: value too long for type character varying(16) in /Library/WebServer/Documents/includes/database.pgsql.inc on line 139.
* user warning: query: INSERT INTO watchdog (uid, type, message, variables, severity, link, location, referer, hostname, timestamp) VALUES (0, 'anonymous_contact', '%name-from sent %name-to an e-mail.', 'a:2:{s:10:"%name-from";s:26:"kevinp@FOO.BAR";s:8:"%name-to";s:8:"rebeccab";}', 5, '', 'http://FOO.BAR/user/26/contact_form', 'http://FOO.BAR/user/26/contact_form', '11.22.33.44', 1288249801) in /Library/WebServer/Documents/modules/dblog/dblog.module on line 147.

I have no idea. Any suggestions?