Redirect non-existing URLs to home page

[BassMan]

Hi,

I would like to redirect non-existing URLs to my homepage. I've tried with this in my .htaccess, but it does not redirect as expected:

<IfModule mod_rewrite.c>
  RewriteEngine on
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteRule ^(.*)$ / [L,QSA]
</IfModule>

My forum is located in a subfolder.

Need some help here, please Thank you.