Inferring from the error message, you are attempting to update the system libraries as a user not having super-user privileges, so does this work for you ?? 
sudo perl -MCPAN -e shell

[download]
A user level that continues to overstate my experience :-))

In reply to Re: what should I do before using the cpan command ? by Bloodnok
in thread what should I do before using the cpan command ? by Anonymous Monk

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