Currently working in a localhost environment for testing before going live.

In a slave site, the links within a shared articles are not forwarding to other shared articles within the same site. The link either defaults to the homepage or produces a 404 error article not found.

Is there a certain format I should use when creating a link in a master website article so internal links will work on a slave site? I've been using Linkr.

Have you tested the Symbolic Link as described in the tutorial video 3 to 7 ?
www.jms2win.com/tutorial#jms12x-7

If YES did you applied the procedure described in the tutorial video 9 with exactly the same value (copy / paste).
www.jms2win.com/tutorial#jms12x-9

Does it works ?

You say that you are working on a localhost.
On which platform ?
Are you using a linux platform ?
I remember also that when working on localhost, you probably have to apply the procedure described in the user manual chapter 9.

It turned out to be a problem with the alias not being the same on master and slave site. Once we made the alias match on the Menu manager for that particular shared article it worked!