use warnings;
use strict;
my $option = 1;

while ($option != 0){
    print "Please select:\n\n";
    print "1 Deutsch\n";
    print "2 English\n";
    print "0 Exit\n";
    print "\nYou've selected: ";
    $option = <STDIN>;
    print "\n";
    if ($option == 0){
        print "You've choosen!\n";
    }
    elsif ($option == 1){
#Hier müsste der Fehler sein!!!
        my $de_result = qx(/de/index_de.pl);
        print $de_result;
    }
    elsif ($option == 2){
        my $result = qx(/en/index_en.pl);
        print $result;
    }
}