I got stuck at this quest. Anyone has the same bug?

Nope...make sure you have a quill and inkwell in your possession, otherwise it wont let you rig the books.

I've rigged the books for The Numbers Jobs quests plenty of times without a quill and inkwell in my inventory o_O

Doesn't for me....maybe it is bugged afterall. The inkwell and Quill makes much more sense...unless he can write with ink from his finger, how else would you change things in a book?