Clean install of ADE 4.5 after computer refresh.
When trying to authorize with Adobe ID as Book vendor the error message
Incorrect ID/PW for the selected vendor, please retry.
The same credentials works perfect when login to the Adobe web.
Resetting PW did not make any difference.
Trying to set up another Adobe Id from within ADE (using the same id) fails as expected.
I would hate to set up another id as I then would loose all my books.
I have exactly the same problem. I contacted Adobe Help via a Chat and the person there referred me to this forum to get the answer. After reading the forum it appears that there is no answer.
My opinion of Adobe Help has just dropped to a very low level.
Try to reset your password and used only Letters and Numbers.