Fatal error: Call to undefined function subscriptions_content_autosubscribe()

I am using latest -dev version (August 04) with Drupal 6.3.

Whenever I do something that should call subscriptions (post new content, new comment, etc.) I get an error:
Fatal error: Call to undefined function subscriptions_content_autosubscribe() in path_to_drupal/modules/subscriptions/subscriptions_content.module on line 647

The content update is happening (i.e. new content is getting posted, comment is posted) but no subscriptions are generated.

I'm new to Drupal, so I don't know what other information would be needed to help identify the problem here.