Most Adobe DRM books use your standard Adobe ID; but some vendors use the Adobe mechanism with their own userid/password.
You need to check with the book vendor, who should be able to tell you which ID/password to use and how to register it with ADE.
I have heard that for some vendors the ID is the email ID you used to register with the vendor,
and the password is the credit card number with which you made the purchase.
The generally more reliable ADE1.7.2 does not support Vendor ID, you must use 2.0/2.0.1