You seem to be loading a file more than once that defines functions. That shouldn't really happen. Are you doing do "somefile.pl" to load the function definitions? If so, you shouldn't be. You should be using require "somefile.pl" instead. But then again, you haven't shown any code at all, so I could be entirely wrong.

You can use diagnostics module to understand many warnings and errors...

Using this code:

use warnings;
use strict;

sub a{ 1 };
sub a{ 2 };

Diagnostics says:

$ perl -Mdiagnostics x
Subroutine a redefined at x line 6 (#1)
    (W redefine) You redefined a subroutine.  To suppress this warning, say

        {
        no warnings 'redefine';
        eval "sub name { ... }";
        }

.............