Most of Perl error message is clear and can be easily guessed out, but some not.

You can find a complete list of Perl's error messages and warnings with explanatory text in the perldiag manpage.

You can also use the splain program (distributed with Perl) to explain the error messages:

    perl program 2>diag.out
    splain [-v] [-p] diag.out

or change your program to explain the messages for you:

    use diagnostics;

or

    use diagnostics -verbose;