this module looks ultra-tasty and I hope I can help with testing (sorry, not a coder). So here we go:
I can add widgets to the dashboard (the comments widget and custom widgets) but they do not appear. I do receive a nasty warning message:
user warning: Unknown column 'visibility' in 'field list' query: SELECT widget_id, type, subtype, conf, col, visibility FROM dashboard_widget WHERE page_id = 1 ORDER BY weight in C:\Users\David\Sites\acquia-drupal-site\acquia-drupal\sites\all\modules\dashboard\dashboard.page.inc on line 54.
Tried with Acquia Marina and Garland, flushed caches, ran cron.