Share the message as suggested.
If you are on XP before SP3 it is worth trying ADE1.7.2 instead, indeed, it is worth it on any OS.
There are lots of bugs in ADE2.0. 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. http://helpx.adobe.com/digital-editions/kb/cant-install-digital-editio ns.html