Forums warning messages

When I try to post new topic this error appears

warning: Invalid argument supplied for foreach() in /web/org/modules/node/node.module on line 561.
warning: implode() [function.implode]: Invalid arguments passed in /web/org/modules/node/node.module on line 565.
user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1 query: SELECT n.nid, n.vid, n.type, n.status, n.created, n.changed, n.comment, n.promote, n.sticky, r.timestamp AS revision_timestamp, r.title, r.body, r.teaser, r.log, r.format, u.uid, u.name, u.picture, u.data FROM drupalorg_node n INNER JOIN drupalorg_users u ON u.uid = n.uid INNER JOIN drupalorg_node_revisions r ON r.vid = n.vid WHERE in /web/org/includes/database.mysql.inc on line 174.
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I am filling captcha, and my topic is successfully posted, but there is this warnings:

warning: Invalid argument supplied for foreach() in /web/org/modules/node/node.module on line 561.
warning: implode() [function.implode]: Invalid arguments passed in /web/org/modules/node/node.module on line 565.
user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1 query: SELECT n.nid, n.vid, n.type, n.status, n.created, n.changed, n.comment, n.promote, n.sticky, r.timestamp AS revision_timestamp, r.title, r.body, r.teaser, r.log, r.format, u.uid, u.name, u.picture, u.data FROM drupalorg_node n INNER JOIN drupalorg_users u ON u.uid = n.uid INNER JOIN drupalorg_node_revisions r ON r.vid = n.vid WHERE in /web/org/includes/database.mysql.inc on line 174.

Using Opera 10.53 if that matters.