the current version of the jrSearch module has this as its schema.php file
function jrSearch_db_schema(){
.............
$_tmp = array(
"s_module VARCHAR(64) NOT NULL DEFAULT ''",
"s_id INT(11) UNSIGNED NOT NULL DEFAULT '0'",
"s_mod TINYINT(1) UNSIGNED NOT NULL DEFAULT '1'",
"s_text TEXT NOT NULL",
"UNIQUE s_unique (s_module, s_id, s_mod)",
"FULLTEXT s_text (s_text)"
);
$_db = jrCore_db_query("SHOW VARIABLES WHERE Variable_name = 'version'", 'SINGLE');
if ($_db && is_array($_db) && isset($_db['Value'])) {
$ver = $_db['Value'];
}
else {
$msi = jrCore_db_connect();
$ver = mysqli_get_server_info($msi);
}
if (strpos($ver, '-')) {
list($ver,) = explode('-', $ver);
}
$engine = 'MyISAM';
if ($ver && $ver > 5.5) {
$engine = 'InnoDB';
}
jrCore_db_verify_table('jrSearch', 'fulltext', $_tmp, $engine);
.........
}
So it seams like the issue you're hitting is taken into account on the current repo version. Probably that hasn't been released in your version.
Solution is:
* wait for the next release OR
* add that code to your jrSearch/schema.php OR
* upgrade your database version to MySQL 5.6+