Added backticks to column names when using insert_string and update_string.  Relates to this bug report:  http://codeigniter.com/bug_tracker/bug/4509/
diff --git a/system/database/DB_driver.php b/system/database/DB_driver.php
index 1450a06..b937ffd 100644
--- a/system/database/DB_driver.php
+++ b/system/database/DB_driver.php
@@ -911,11 +911,10 @@
 		

 		foreach($data as $key => $val)

 		{

-			$fields[] = $key;

+			$fields[] = $this->_escape_column($key);

 			$values[] = $this->escape($val);

 		}

 				

-		

 		return $this->_insert($this->prep_tablename($table), $fields, $values);

 	}	

 	

@@ -940,7 +939,7 @@
 		$fields = array();

 		foreach($data as $key => $val)

 		{

-			$fields[$key] = $this->escape($val);

+			$fields[$this->_escape_column($key)] = $this->escape($val);

 		}

 

 		if ( ! is_array($where))