Jules, pardon me if I didn't get back to you.
In another post, you asked for a list of supported devices, and I just
answered that one. iPads are NOT supported by ADE.
If you get a HTTP 404 message, that's telling you that the file/site you're
trying to get to isn't there. It's not an ADE issue, but an internet
issue. You may have seen it before, when you tried to go to a site on the
Internet and the address wasn't right.
The license message is saying that there's an error in the communication
between your computer and the site you're trying to reach, and again has
nothing to do with ADE itself.
As for the number of devices.... I think ADE's statement here is
misleading, but the crux if the issue is how that device count is kept.
It's not reset if you drop a device or reinstall ADE, which I think it
should be. In order to clean it out, you can uninstall the software on your
Windows PC, and delete any remaining folders under Adobe Digital Editions,
then EMPTY THE TRASH. That cleans out your registry as well as the hard
disk of any files that Adobe might look for when it's installing itself.
(Technically, it appears ADE checks for previous versions and if it finds
one, then it preserves certain keyfiles including the one that holds the
attached device count).
If you go for the deletion route, you should go into your Digital Editions
folder and move all of the books, pdf's, etc. that are in there to another
folder somewhere else. You can move them back after reinstalling ADE, but
you will have to add them back to the library one at a time.... Bummer.
Finally, consider the purpose you're using ADE for. It sounds to me as
though you think of ADE as a repository of books that people can access,
which is true, but in a limited sense. ADE isn't an ebook database to be
used for general access - nor was it designed that way. It's a file
management system for a person or perhaps a family to use to contain books
that they're going to read. You may be expecting more from it than it can
deliver. If you need or want to have more general access, I think that the
Overdrive software may be something you should look at: it is robust enough
to be used by libraries....
Hope this helps!