There are lots of bugs in ADE2.0 (and 2.0.1). Try replacing ADE2.0 with the older but more reliable v1.7.2.
(You can have them both installed at once if you like.)
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
Some people have found ADE trying to upgrade automatically.
It appears (not 100% sure) that if you install ADE2.0 as a new install (not as an upgrade) that your 1.7.2 will continue to run.
Probably best to say no if 2.0.x installation asks if you want to migrate your library.
i installed ADE 1-7-2 used it to open my file, and got this error message:-
Adobe DRM Error
Message: Error on response from server.
Scroll below or view error.log for more details.
Your Adobe software could not be activated.
HTTP error on Adobe DRM Activator request.
Adobe DRM Activator error.
Client Code: 31 - HTTP Code: 555
Fault location: 15
hmm, not very helpful.
Did you authorize v1.7.2 with the ID that was in use when you first accessed the book (when you bought it) before trying to read it now?
It may be worth deactivating it (ctrl-shift-D) and reactivating it.
I should have mentioned that above; activation often gets confused on reinstall of ADE ~ sort of half working and half lost.