I think you're making some assumptions. Digital Editions is intended for
individuals who download ebooks and other epublications from websites that
sell or distribute them. Its design is for 1:1 application - one user, up
to two computers and up to four ereaders. That's it. It is not able to
scale for more users, nor is it able to run on a server with clients
interfacing with it.
The error you're getting is telling you this - in a sort of twisted way.
Sorry but I'm not confusing... Each computer has a single installation of ADE and each user will have his own Adobe Account.
I just would like to know what's meaning this error code exactly?
That's still a bit confusing, because we don't know if you intend to share
computers among users, which will not be supported.
To your other question: unfortunately, the developers of Digital Editions
did not leave a codex of the error messages, so we can't look up what this
message is intended to tell you. There are others on the forum who are
either current or former employees who SHOULD be able to find out - I'm
surprised they haven't responded yet....