Is it possible that @INC was changed by the upgrade? Perhaps (just guessing) 5.00(5.3?) was installed under an unusual or specific directory structure, upon which the script depends?
p.s. anyway, to directly answer your question, type
perldoc perldelta
(and now I see that Albannach++ beat me to this update.)
mkmcconn

In reply to Re: changes between Perl v5.00? to v5.6 by mkmcconn
in thread changes between Perl v5.00? to v5.6 by skunspauk

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