10.6.7 fixed an issue a number of our customers were having with videos not previewing or playing back properly in the Wiki that had been created by Podcast Producer.  However it also broke video playback in IE and Firefox because of an issue with the previews.

Fortunately Apple has posted a script to resolve this at the link below:

http://support.apple.com/kb/TS3747

Written by: David Colville on April 5, 2011.