I spent the last hour or so searching for the correct .htaccess file for installing Drupal Clean URLs (Drupal 6.xx) on MediaTemple’s server without any luck. Finally, I was able to piece something together that worked and I thought it would be worth sharing:

< IfModule mod_php5.c>
  php_value magic_quotes_gpc 0
  php_value register_globals 0
  php_value session.auto_start 0
  php_value mbstring.http_input pass
  php_value mbstring.http_output pass
  php_value mbstring.encoding_translation 0
< /IfModule>
< IfModule mod_rewrite.c>
  RewriteEngine on
  RewriteBase /YOUR-SUBDIRECTORY-NAME-HERE
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteRule ^(.*)$ index.php?q=$1 [L,QSA]
< /IfModule>

I hope that this helps someone in the future.