You have to distinguish between perl (the compiler/interpreter) and Perl (the language).
in reply to How to answer "Perl is not secure" objections?
As for the program, I'd like to point you to the Common Vulnerabilities and Exposures List, search for Products -> Perl (don't enter 'perl' in the search box, it will find 'properly' as well).
Now compare these results to other interpreters and virtual maschines.
As for the language: you don't have to mess with your memory on your own (like C), you have tainting, no insecure register_globals (or whatever that stuff is called in PHP).