The "Unable to create target folder" is very clear and mean that you can not create the target directory.
This is probably a permission issue and you have to check that you have the permission to create a directory in the target place.
If you are using the FTP layer, see the tutorial video 15 that explain the procedure.
www.jms2win.com/tutorial#jms12x-15
So hosting provider may use different "ower" for the files and use a "apaches" user to create files and folders that may be different of the "index.php" owner that is used.
Sometimes such kind of environment does not allow using the 777 permission to allow cerate files and folders.
If you expect to deploy a slave site into another directory, it is mandatory that you have the correct permission because the FTP layer will not help you to create the symbolic links.
The FTP protocol does not contain any statement that allow create symbolic links.
So you have to consider that FTP layer does not exists to check the Symbolic Links permissions.
If the SYmbolic Links workis in the subdirectory created in /multisites, this probably means that you have effectivelly a permission issue somewhere that does not autorize to deploy your slave site.
Contact you hosting server administrator to help you solve the permission issue.
If you want that we have a look on your server, you can order our billable support at
www.jms2win.com/download?page=shop.produ...35&category_id=1