Over the past few days we have been getting
reports from members of MobileRead that Fictionwise has started blocking Kindle PIDs. I just checked my account, and it's happened to me, too.
If you have a Kindle registered at Fictionwise, you will need to log in to your account and request that Fictionwise Support remove or replace that PID before downloading and Kindlizing another Mobipocket ebook. You cannot do it yourself, unfortunately.
It's possible for Fictionwise to do this because all the Kindles have a PID that is slightly different from the other Mobipocket devices (they have an asterisk "*" as the eighth character of the PID). I bet this was a deliberate design choice on the part of Amazon/Mobipocket. I believe this because
www.Mobipocket.com drops the asterisk from a PID. Most of the other Mobipocket retailers also drop the asterisk. Fictionwise was the only major ebook retailer that did not.
It looks to me like Amazon/Mobipocket is pressuring retailers to close the few remaining loopholes that let Kindle owners buy ebooks from anyone other that Amazon. However, I may be jumping to conclusions because only existing Kindle PIDs are disabled. If you remove the bad PID, you can reenter it and it will be accepted as valid.