Yes, I meant to put this in my comment above.

He can read through Error-handling-and-messages in the perlmodstyle page.

Specifically:

croak() only when your module absolutely cannot figure out what to do. (croak() is a better version of die() for use within modules, which reports its errors from the perspective of the caller. See Carp for details of croak(), carp() and other useful routines.)/p>