@TigerTran What Linux OS do you have? My guess is you have Ubuntu, right?
Did you read what is mentioned in the official release message? https://forums.fogproject.org/topic/13488/fog-1-5-7-officially-released
Please make sure you say NO if asked about removing and re-installing PHP and Apache when upgrading to 1.5.7 on Ubuntu!!! There is an issue within the installer trying to switch to MariaDB that causes a problem on Ubuntu installs otherwise. If you have such an issue see here: https://forums.fogproject.org/post/126476 and https://forums.fogproject.org/topic/13447/lost-database