What operating system are you using and what happens when you try to install Digital Editions?
Now I found the solution why ADE is not working on windows or Android phone/ tablet.
Here is the answer:
1. ADE requires atleast IE 10 to run on windows.
2. If you want to run your ebook on Android even if it ePub3.0 through ADE 4.0 or higher you need to disable you "android system webview" app first.
Hope this will work.