wp_tag_cloud — displaying for each site?

i have multisite running and see that on the tag cloud widget, each blog displays its own tag cloud terms.

However, i want to also show the tag cloud on non-wordpress pages and i can’t get the tag cloud display to work.

prior to WP 3.0, i used this simple code to do that:
-php-
wp_tag_cloud( $args );
-php-

and it worked fine. but now with multisite running, it doesn’t work?

what do i have wrong?
i don’t get any errors, etc.
just nothing shows up.

thanks!!