Could it be that when you run perl Makefile.PL you run the default Perl? You could edit the Makefile.PL to point to your perl 5.16.1.
in reply to Specify particular Perl path to a module during installation
A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James
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