Added a default _insert_batch() method instead of requiring each driver to define it and fixed 2 issues related to it
diff --git a/system/database/DB_active_rec.php b/system/database/DB_active_rec.php
index b324226..2bb8913 100644
--- a/system/database/DB_active_rec.php
+++ b/system/database/DB_active_rec.php
@@ -1219,6 +1219,23 @@
 	// --------------------------------------------------------------------
 
 	/**
+	 * Insert_batch statement
+	 *
+	 * Generates a platform-specific insert string from the supplied data.
+	 *
+	 * @param       string  the table name
+	 * @param       array   the insert keys
+	 * @param       array   the insert values
+	 * @return      string
+	 */
+	protected function _insert_batch($table, $keys, $values)
+	{
+		return 'INSERT INTO '.$this->protect_identifiers($table).' ('.implode(', ', $keys).') VALUES '.implode(', ', $values);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * The "set_insert_batch" function.  Allows key/value pairs to be set for batch inserts
 	 *
 	 * @param	mixed