PANIC: SQL syntax error blocks entire site

My entire site just went down, I hope someone can help.

I got the following error (having turned on error messages in Administration under Configuration / System):

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JDatabaseMySQL::query: 1064 - 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 'u.id = 62 OR u.id = 66 OR u.id = 72 OR' at line 7 SQL=SELECT u.id AS id, u.name AS name FROM jos_users AS u WHERE u.id = 64 u.id = 62 OR u.id = 66 OR u.id = 72 OR

Call stack
# Function Location
1 JSite->render() index.php:79
2 JDocumentHTML->render() includes/application.php:168
3 JDocumentHTML->_parseTemplate() libraries/joomla/document/html/html.php:249
4 JDocumentHTML->getBuffer() libraries/joomla/document/html/html.php:386
5 JDocumentRendererModules->render() libraries/joomla/document/html/html.php:190
6 JDocumentRendererModule->render() libraries/joomla/document/html/renderer/modules.php:41
7 JModuleHelper->renderModule() libraries/joomla/document/html/renderer/module.php:84
8 require() libraries/joomla/application/module/helper.php:173
9 GKNews_MainHelper->getDatas() modules/mod_gk_news/mod_gk_news.php:34
10 GKNews_DBHelper->getAuthorArray() modules/mod_gk_news/helpers/main.helper.php:120
11 JDatabaseMySQL->loadObjectList() modules/mod_gk_news/helpers/db.helper.php:252
12 JDatabaseMySQL->query() libraries/joomla/database/database/mysql.php:458
13 JError->raiseError() libraries/joomla/database/database/mysql.php:231
14 JError->raise() libraries/joomla/error/error.php:171
15 JException->__construct() libraries/joomla/error/error.php:136
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It's easy to see that the SQL syntax is wrong, but how can I fix this??

I have full access to the admin interface as well as other .php pages on the site - but the entire joomla frontend is down.

Please help.

Best regards
Dane

Update: Disabling the GKNews module brings the site back up, so "panic" is now replaced with "please help me as soon as you can". I can't see all the news categories on the front page any more, so it's really ugly...

Any help is deeply appreciated, thank you.

The error can be recreated at: [removed]

Problem solved, case closed. Don't know what I did, but now it works.