Subscribe2 : maybe_add_column()

I’ve just upgraded to 2.0.3 and wanted to add the Subscribe2 plugin (most recent version).

This is the error message I get upon plugin activation:

Fatal error: Cannot redeclare maybe_add_column() (previously declared in /blog/wp-content/plugins/subscribe-to-comments.php:245) in /blog/wp-admin/upgrade-functions.php on line 375

What do I do about this?

Thanks!