Comments submitions are broken

Hi everybody,

I have my blog hosted in my own server and there are something wrong for 2 weeks ago.

The mistake is when some user wants write a comment in some post. The comment was submitted, but the page prints a warning error when check ip to insert (or not ) into the blacklist.

The warning is like:

Failed to query blacklist: ip – x.x.x.x. Query: SELECT * FROM sk2_blacklist WHERE (value = ‘x.x.x.x’ AND (type = ‘ip_black’ OR type = ‘ip_white’)) AND score > 30 ORDER BY score DESC
SQL error: Unknown character set: ”
Failed to query blacklist: domain – domain.com. Query: SELECT * FROM sk2_blacklist WHERE (value = ‘domain.com’ AND (type = ‘domain_black’ OR type = ‘domain_white’)) AND score > 30 ORDER BY score DESC
SQL error: Unknown character set: ”
Failed to query blacklist: regex_match – domain.com. Query: SELECT * FROM sk2_blacklist WHERE id IN(-1) AND score > 30 ORDER BY score DESC
SQL error: Unknown character set: ”
Failed to query blacklist: regex_content_match – Moooooooolt xulo!!!!. Query: SELECT * FROM sk2_blacklist WHERE id IN(-1) AND score > 30 ORDER BY score DESC
SQL error: Unknown character set: ”
Failed to query blacklist: domain_grey – domain.com. Query: SELECT * FROM sk2_blacklist WHERE (value = ‘domain.com’ AND type = ‘domain_grey’) AND score > 80 ORDER BY score DESC
SQL error: Unknown character set: ”
Failed to insert blacklist entry: ip_white – x.x.x.x.
SQL error: Unknown character set: ”
Failed to insert blacklist entry: domain_white – domain.com.
SQL error: Unknown character set: ”
Error: cannot update comment entry ID: 19483 to status: approved.
SQL error: Unknown character set: ”
Failed inserting/updating sk2_kSpamTable record for comment ID:19483 (mode: overwrite).
Query: INSERT INTO wp_sk2_spams SET karma = 2001,karma_cmts = ‘a:5:{i:0;a:4:{s:2:\”ts\”;i:1274373259;s:3:\”hit\”;d:0.5;s:6:\”plugin\”;s:18:\”Javascript Payload\”;s:6:\”reason\”;s:39:\”Valid Javascript payload (can be fake).\”;}i:1;a:4:{s:2:\”ts\”;i:1274373259;s:3:\”hit\”;d:0;s:6:\”plugin\”;s:17:\”Encrypted Payload\”;s:6:\”reason\”;s:37:\”Encrypted payload valid: IP matching.\”;}i:2;a:4:{s:2:\”ts\”;i:1274373259;s:3:\”hit\”;d:0.5;s:6:\”plugin\”;s:12:\”Link Counter\”;s:6:\”reason\”;s:50:\”Comment has no URL in content (but one author URL)\”;}i:3;a:4:{s:2:\”ts\”;i:1274373261;s:3:\”hit\”;d:1000;s:6:\”plugin\”;s:15:\”Snowball Effect\”;s:6:\”reason\”;s:128:\”Commenter granularity (based on URL): 625 old comment(s) (karma avg: 253.330000), 15 recent comment(s) (karma avg: 1488.460000).\”;}i:4;a:4:{s:2:\”ts\”;i:1274373261;s:3:\”hit\”;d:1000;s:6:\”plugin\”;s:15:\”Snowball Effect\”;s:6:\”reason\”;s:129:\”Commenter granularity (based on email): 419 old comment(s) (karma avg: 309.720000), 1 recent comment(s) (karma avg: 2001.000000).\”;}}’, unlock_keys = ‘a:0:{}’, remaining_attempts = 5,last_mod = NOW(), comment_ID = 19483
SQL error: Unknown character set: ”
Sorry, but your comment has been flagged by the spam filter running on this blog: this might be an error, in which case all apologies. Your comment will be presented to the blog admin who will be able to restore it immediately.
You may want to contact the blog admin via e-mail to notify him.

I don’t know if some plugin can make this warning on WordPress.

The comments are submitted and inserted into our database, but aren’t visible in my home page. To view at main page, I must edit the comments and save it again through Administration page

Must I upgrade WordPress version?

Thanks