my $a = qw(0,100);

Further to davido's comments above about this very suspicious statement: You don't seem to be using warnings, otherwise you'd get one about this semantic usage:

c:\@Work\Perl\monks>perl -le
"use warnings;
 use strict;
 ;;
 my $s = qw(0,100);
 print qq{'$s'};
"
Possible attempt to separate words with commas at -e line 1.
'0,100'
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It's always wise to enable warnings (and strict syntax restrictions as well), especially if you are a novice Perler (and in this case, see also diagnostics).