I recently migrated my 6.05 portal to 6.1 GA2. I used the automatic upgrade process to perform this migration. Everything seems to be working but when I click the permissions button for a page the panel opens but all I see is $theme.include($content_include) being displayed.

The following exception is also thrown in the portal's console:
Sep 10, 2012 7:05:35 PM org.apache.catalina.core.ApplicationDispatcher invoke
SEVERE: Servlet.service() for servlet default threw exception
java.io.FileNotFoundException: The requested resource (/html$tilesContent) is not available

See https://www.liferay.com/community/forums/-/message_boards/message/16274809 for the solution to this issue.