Based on your reply, it seems that you didn't setup the JMS Template rule to isntall a joomla template in a slave site as the at the last question you mentioned that the "template folder" parmeter is empty.

In the previous case of markredmond, the scenario was to allow installing a joomla template in the slave site.
When doing that on Joomla 1.7, we identified a bug that we fixed internally and that will be available in the next release of JMS.

I have exactly the same problem as the topic starter.

About your questions:

Do you have a Joomla "/templates" symbolic link ?
>> Don't really know what you mean by this. There is a /templates directory in the root of my main joomla installation.

DO you have a copy of the "/templates" directory ?
>> Copy of what to where ? There is a /templates directory in my multisites/domain directory as well.

Do you have setup a specific value in the JMS templates concerning the "Templates (themes) folder"
>> Yes

Symbolic Link is the equivalent on windows of the short cut or in apple the equivalent of the alias.

So it is important that you can identify if you have a physical directory or a link.

You mentioned that you have a "templates" directory in the slave site "multisites/domain" directory and you also mentioned that you entered something the "themes folder".

Which value did you entered in the "themes folder" ?
Is this {deploy_dir}/templates

Do you have deployed the website in the directory {site_dir}

As you mentioned /multisites/domain, did you created a domain in your server and if yes, do you use cPanel and did you setup an addon domain ?
If addOn domain, did you specifed the document root that correspond to the full path to the multisites/domain directory ?

The /templates is a real directory, not a shortcut

Themes folder: i tried {site_dir}/templates first, after that I put the whole path in it myself, no change. Now I tried {deploy_dir}/templates : no change, still the same effect.

The website itself is showing the default joomla template. So it looks as if the linking worked ok. It was created in Plesk (we don't have cpanel on our server) as a domain alias.

On the main site, we already installed an other template, and that works ok.

The parameter is used at the moment that the website is created.
If you change the parameter it will not have any effect as soon as the "/templates" directory or symbolic link is already present.
JMS does not delete an existing directory or symbolic link.
You have to do it manually if you want.

For me, you have a symbolic link and not a physical directory for the templates.
Check also the directories inside the "/templates" directory and use a SSH terminal to verify that you have symbolic link or physical directory.
Some "file manager" or FTP tools does not display the difference between a physcial directory. So the only way to be sure is to use the SSH terminal and the "ls -l" command.

I don't have SSH access, but my program does show the difference between a symbolic link and a physical directory (i checked it on another place where there was realy a symbolic link, it has a quick launch icon).

Now, I tried to remove my subdomain (which worked without problems), and then I tried to reinstall it again so I could make sure the template directory would be working.

Now, for some reason, after the installation (and manual creation of configuration.php in the slave site directory), I ALWAYS keep getting the installation wizard again. It's driving me crazy. I can just keep installing it, and it will always show me the code for the configuration.php file at the end. When I open the frontend or admin of the website, i get redirected to the installation directory.

Any suggestion ? I tried to reinstall with {site_dir}/templates in the template directory again, as this used to work, but it doesn't anymore