I updated a page (/quick/ferpa) on the main blog after installing Sitewide Tags. It updated the tags blog, but gave the page a URL of /tags//ferpa where tags is the blog name (subdirectory install) and //ferpa is the page.
If I click it I get 404.
If I fix the URL to /tags/ferpa I get redirected to /tags//ferpa > 404.
http://wordpress.org/extend/plugins/wordpress-mu-sitewide-tags/