If Tom Christiansen's article indicated above hasn't convinced you, there is a somewhat shortened form of what it is saying in Damian Conway's "Perl Best Practices":

Don't use subroutine prototypes

Now, if that isn't clear enough.. :)

Chapter 9 of the PBP book, "Subroutines", has a section "9.10 Prototypes"; I think the book in it's entirety is worthwhile reading (actually, having it handy) if you enjoy doing things with Perl.

Good luck with those not-quite-friendly prototypes.