Installing to a subdirectory is working but not a sulution.
It must also work in the main directory!!!

The error message that is provided here mention that you have a restriction in your "open_basedir" that forbid the access.

"open_basedir restriction in effect"

So update the permission provided by the "open_basedir" to grant the permission to the directory.

The permission is NOT OK.

Now the story must be finished.
The problem is great and the request of help/support is started from six month .
In most of the forum , the users reports as solution the installation on subfolder.
The problem is not permission's folder , IN SUBFOLDER OF IS ALL OK .
I test , in the same folder , with same permission and with joomla 1.5 and is tutto OK.
JMS in use is last version available.
I want solution at this problem.
It 's useless to repeat the same answers in vai forum.
It should be allowed to join them and find a permanent solution.

Thanks

Try using Joomla extplorer and you will see that you have the same issue with the permission.
Unable to get the list of files and folders when you are on the root directory.

This is not related to JMS.

If you install that on another hosting provider that use for example cPanel and not Plesk, this works perfectly.

The problem is related to the configuration of Plesk and the linux permission.

As you seems to have a problem with the open_basedir, change you Plesk configuration to set the open_basedir with "no value". (disable it).

A solution possible for plesk is :
1. Connect via SSH to server
2. cd /var/www/vhosts/domin_name/conf/
3. With nano o vi open file httpd.include
4. Comment with # the line with open_basedir value content
5. Save the file
6. Restart the service with
service httpd restart
7. After end jobs , delete comment and restart the httpd service.

For edwin2win , the problem aren't the permission of directory.
Flip to the fact that jms it works in subfolder .

Bruno

Thanks that was the part missing.... you can go also in plesk 10 to the php config page and enter for open_basedir the value none.