Thanks for these answers, it runs well with: 
use Cwd;
$ARGV[0] = cwd()."/$ARGV[0]" unless $ARGV[0] =~ /^(\/.*)$/ ; # Abs.
use FindBin qw($RealBin);
chdir "$RealBin/..";
use lib "$RealBin";

[download]
and some minimal file check.

In reply to Re: How to manage correctly a (Tk) application startup? by emilbarton
in thread How to manage correctly a (Tk) application startup? by emilbarton

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