Well I've installed JMS in my website. The host is 000website so Symbolic Link is forbidden. so I create a subdomain like slave.domain.comoj.com

And then I use JMS to create the subdomain and define that URL in the site in JMS configuration. But when I access that url there is no Joomla fresh install, instead of that I only get Index of. message. and when I explore with ftp I see a slave folder in the master directory and multisites also in the master directory with slave dir inside.

Forget to mention using joomla 2.5 and JMS 1.2.x
The files structure is
public/ Here is my main install of joomla alias master
public/slave this folder is created when I use cPanel to create a subdomain
public/multisite/slave created when I use JMS to define a fresh slave site.

I tried also to open the url domain.com/multisite/slave and theres no installation either.

What I'm doing wrong here?

Please help me

When the symbolic link is not allowed, you have to define the subdomain in your server to have the "document root" that point to your master website.

The concept of JMS is to share the joomla application (PHP code) and therefore, you need to configure your server to have the subdomain directory pointing to the amster website directorty.

In your case, you have setup your server to have a subdomain with a specific directory and as the symbolic link does not exists, it is impossible to JMS to deploy the links into this directory.

As you seems using cPanel, when you create the subdomain specify a "document root" that has the same value as your master document root.

If you are using your own server and have a WHM, verify that suPHP is used. This will fix the symbolic link issue.