mod_rewrite and Menalto Gallery

For some reason, even though I set RewriteEngine On in the respective vhost *.conf file, Menalto Gallery keeps claiming:

"For whatever reason, Gallery did not detect a working modrewrite setup. If you are confident that modrewrite does work you may override the automatic detection. Please, run these two tests to see for yourself."

mod_rewrite is listed in the loaded modules via a call to phpinfo().

I'm not sure if I'm missing something. Any ideas would be helpful. Thanks.