It appears from http://support.muse.adobe.com/message/4752196 that the solution to this is to dump ADE2.0 and install the much more reliable 1.7.2.
(1.7.2 is also the solution to lots of other ADE problems)
Version 1.7.2, it is a little difficult to find, available on Adobe site for Windows and for Mac.
The forum software is sometimes corrupting the link above. There shouldn't be a blank in 'editio ns.html'. The following redirects to the same page: http://tinyurl.com/diged172