The problem with Shelfari's database is that unless you create a book just for you, it's limited to Amazon.com's database. A lot of non-North American and British books aren't available unless it's possible to import them (one example of a foreign book possible of import is the Japanese book Another due to its increasing popularity with the weeboo crowd which I am happily associated with).
Now, I'm assuming that's where the ISBN error is coming into play. You're putting in an ISBN that just simply isn't located on Amazon.com's database, which means you'll never find the book here until Amazon gets with the programme and adds more databases than just the .com database.
Unless you're talking about "adding" as in you're making a user created book to add to Shelfari's database and you're adding an ISBN to that and that's where the ISBN error's coming in. In that case, I'd search the book's ISBN and see if there's a conflicting book. I've never made a user created book so I'm not exactly sure what all needs to be put in, but just check that out.
Either way, reply back and let us know if you still need more help with the problem. :)
posted 1 year ago. ( permalink )