You don't seem to understand the explanation given. Please show your HTML. For debugging I suggest you look at the CGI object like this which will confirm the data received:

#!/usr/bin/perl
use CGI;
use Data::Dumper;
my $q = new CGI;
print $q->header(), '<pre>', $q->escapeHTML(Dumper $q), '</pre>';

# this will give you all the values of the checkboxes 
# called param_name that were checked separated by spaces
print join ' ', $q->param('param_name');
[download]

This will show you exactly what your script is getting.

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print