changed escape_str() in mysqli_driver() to use is_object() instead of is_resource() to test $this->conn_id
diff --git a/system/database/drivers/mysqli/mysqli_driver.php b/system/database/drivers/mysqli/mysqli_driver.php
index dab56c7..aaeab57 100644
--- a/system/database/drivers/mysqli/mysqli_driver.php
+++ b/system/database/drivers/mysqli/mysqli_driver.php
@@ -249,7 +249,7 @@
 	 */

 	function escape_str($str)	

 	{

-		if (function_exists('mysqli_real_escape_string') AND is_resource($this->conn_id))

+		if (function_exists('mysqli_real_escape_string') AND is_object($this->conn_id))

 		{

 			return mysqli_real_escape_string($this->conn_id, $str);

 		}