A Prodigious Error Message

For my BarCampMadison2 presentation this year, I prepared a DVD “gift bag” with a lot of material on Functional Programming (FP) and specific FP languages like Scheme and Haskell, and also included DrScheme binaries for Mac and Windows and source for UNIX.
Yesterday I received an email from one of the attendees. He was copying the contents of the DVD to a directory on his UNIX system. In the course of doing so, he got an error message. If you are even superficially familiar with Monads and Haskell (as I am), you will surely find this error message prodigious!

/mnt/cdrom$ cp -R library ~/lisp-library
cp: cannot access `library/Haskell/Monads': Input/output error