[plt-scheme] an misunderstandable error

Hey i am using drscheme 4.2 and my language mode Pretty big
and i am reading plai.Because of this i am using
(require (planet plai/plai:1:3))
but when i try to debug my program to understand the function because almost
all function is from plai book.
I took this error

compile: unbound identifier (and no #%top syntax transformer is bound) in:
num13

How can i fix this error.My program is excuted truly.I am sending an
attachment that involves the code.
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