Hello,
You maybe ablet to try the following redirect. [This can be used to redirect a primary domain to a folder to make it appear as if that subfolder's index.htm, index.php, whatever is the index page for the primary domain. It can also be used to redirect a parked domain to an addon domain so that a person can park (the first page at least) with the parked domain's url]
RewriteEngine On
Options +FollowSymlinks
RewriteCond %{HTTP_HOST}
domain.com$
RewriteCond %{REQUEST_URI} !folder/
RewriteRule ^(.*)$ folder/$1
This is easier to do than moving all the folders to the upper level and having to change any paths.
Best Regards,