Defined our first slave site without a problem. Very simple...just entered the basic required info, siteid,status,owner,and domain name.....

Changed the domain pointer to mulitsite/slave folder within the master site.

in browser I entered the slave domain name and it brought up the first step in the joomla installation process (select language)... whoo whoo!

Clicked next...

Received:
Forbidden You don't have permission to access / on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

Apache/1.3.33 Server at www.(myslavesite).com Port 80

Deleted the slave site and tried it again, but now I just get the 404 error without the first step of the joomla install process...

Like many others apparently...based on the message from JMS slave create:

* - You can now map your new domain (www.slave.com) to the directory
* '/home/content/a/z/u/elpatron/html/master/multisites/slave'.

That is what I did...but in fact after I pointed the domain to the master folder.....

this can be closed as resolved by customer...jms may want to clarify this message

JMS can work with both directory.
Originally (JMS 1.0.x), it was not possible to deploy a slave site into a specific directory and the only solution was to share the same directory than the master.

When the Symbolic Link functionality were implemented, it is possible to deploy the slave site into this specific directory to benefit of specific images and templates folder.
This is also easier for hosting administration tools that does not allow to change the directory assign to a domain or a subdomain.
In this case you have to deploy the slave site in the directory provided by your hosting administration tool.

In your case, the "Forbidden" access is sometimes due to a problem of permission.
So check the permission and owner of the files present in the deploy directory.