How sure are you that the drm on the book is one of the PIDs that you are trying. I (and several other people) ran into this same error because the PID that we input was not the actual PID on the book. Maybe you can get someone that is successfully using Mobidedrm to do a test for you and then you would at least know whether it's an installation problem or an incorrect PID.
I wondered about this. I thought the PID related to the device (ie my PC) rather than the book but, just to be on the safe side, I re-registered my PID with the vendor (BOB) then re-downloaded the book (so, presumably, the book was then 'tagged' with that PID?). I then put
that book through the same system.....and got the same result - invalid PID checksum. How can that be, if BOB accepted it as a valid PID?
Yours, more confused every minute, etc........
