Do you have the latest version of Calibre? 0.4.100 is the current version. Another question is what version MobiDeDRM.py do you have? if you have 0.01, you'll need to find 0.02. If you have 0.02 you'll need to update it to 0.04. Thsin link to find the patches that you have to apply yourself to 0.02 are in
https://www.mobileread.com/forums/sho...142#post222142. The error you have is possibly due to the wrong version of MobiDeDRM.py being used on that book.