Is there a way to access to the users websites instead the main site web? i mean, access to the folder "web" under "web111_jhon"?
Ofcourse, why not? One way is to type url "www.yourdomain.com/web111_jhon/web/" Other way is to create a sub domain for that user. So you'll just type (for example) john.yourdomain.com For creating a subdomain, use search on this forum. Many words spoken already.
Have a look at chapter 2.2.9 here: http://www.ispconfig.org/downloads/manual_en/manual_kunde_en_src.htm#4_2_2