There are lots of bugs with ADE2.0, many of which are resolved by installing the earlier 1.7.2.
I haven't seen this particular bug as a v2.0 specific problem, but it may be worth giving 1.7.2 a try.
Version 1.7.2, it is a little difficult to find, available on Adobe site for Windows and for Mac.
http://helpx.adobe.com/digital-editions/kb/cant-install-digital-editio ns.html
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