I just got it working in my test/dev 3.6.4. forum and will be installing in my live forums. Works like a champ too!
I had to make the following changes to the loo_sql_searchplug.php though. (Please note) I'm not the author so I hope it is OK to show how I got it to work, plus I can not support either. Sorry.
Too bad this is not a standard "out-of-the-box" feature for vB.
Original
PHP Code:
// add phrases to master set
$db->query_write("INSERT INTO " . TABLE_PREFIX . "phrase (languageid, phrasetypeid, varname, text) VALUES ('-1', '5000', 'setting_searchloolimit_desc', 'Just like the *NIX load limit setting, but only prevents access to searching when the server load is too high')");
$db->query_write("INSERT INTO " . TABLE_PREFIX . "phrase (languageid, phrasetypeid, varname, text) VALUES ('-1', '5000', 'setting_searchloolimit_title', 'Search Server Load Limit')");
NEW
PHP Code:
$db->query_write("INSERT INTO " . TABLE_PREFIX . "phrase (languageid, phraseid, varname, text, product, fieldname) VALUES ('-1', '5000', 'setting_searchloolimit_desc', 'Just like the *NIX load limit setting, but only prevents access to searching when the server load is to high', 'vbulletin', 'vbsettings')");
$db->query_write("INSERT INTO " . TABLE_PREFIX . "phrase (languageid, phraseid, varname, text, product, fieldname) VALUES ('-1', '5001', 'setting_searchloolimit_title', 'Search Server Load Limit', 'vbulletin', 'vbsettings')");