I had exactly the same problem. Try to unauthorize ADE, if you can't, do the following gave by Shreva.
"If due to some reason, you are unable to deauthorize ADE, follow the below steps:
Mac: Navigate to /Users//Library/Application Support/Adobe/Digital Editions and drag the activation.dat file to the trash.
ADE will be deauthorized now.
Now Authorize ADE again.
Choose Start > Run.
In the Open text box, type regedit and then press Enter. The Registry Editor opens.
In the left pane of the Registry Editor, locate the following registry key:
Right-click the Adept key and choose Delete.
In the Confirm Key Delete dialog, click OK.
Your authorization will be deleted.
ADE will be deauthorized now. Reboot your PC
Now Authorize ADE again."
I did that, but unfortunatly, even if I have my ID and my pass, ADE refuse to record me (Server Problem I think) then I try 'Open ADE without ID', and then, I could charge all my books again. But I was asked to enter my ID et my password for each book.
Hope this help. And thank to Shreva.
I have the same problem. I uninstalled & reinstalled ADE from my computer. Now I can download a library ebook again, but it won't open in the Kobo ereader.
I tied the Adobe chat support - but they don't support this software