gregor42, thanks.. I guess it seemed obvious to me.. but probably not to anyone else..

First of all, the code is just a modification of the XML::Parser example code.

#!/usr/bin/perl -w
use strict;
use XML::Parser;

# initialize hash that will hold header info
my $parser = new XML::Parser(ErrorContext => 4,Handlers => {Start => \
+&handle_start,
                                          End   => \&handle_end,
                              Char  => \&handle_char});
my $counter =0;
my @tagdesc;
my %tags;
# parse the file whose name we specified as a command-line parameter
$parser->parsefile(shift);
open(OUTPUT, ">tag.desc") or die "No open";
foreach my $keyval(keys %tags) { print OUTPUT $keyval, "\n"; }
close OUTPUT;

sub handle_start {
    my $p = shift;
    my $el = shift;
    my %attribs = @_;
   if($el eq 'product_data') { $counter ++; }
   if($counter) { push(@tagdesc, $el); }
}

sub handle_char {
    my ($p, $data) = @_;
    # print $data,"\n" if $counter;
}

sub handle_end {
    my $p = shift;
    my $el = shift;
    my %atrribs = @_;
    my $not_written = 0;
    if($el eq 'product_data') { $counter --; $not_written = 1;}
    if($not_written) {
        my $str = join(':',@tagdesc);
        @tagdesc = ();
        if(exists $tags{$str}) { my $cnt = $tags{$str}; $cnt++; $tags{
+$str} = $cnt; }
        else { $tags{$str} = 1; }
        $str = undef;
        $not_written = 0;
    }
}
[download]

Unfortunately, the link isn't publically available... and I hope I did an ok job of defining what the weird characters are in the previous post...

finally, thanks for the XML::Parser review.. I did learn from it.. but unfortunately, not enough to solve this problem :o(.. as another question, where can I find XML::UM or anything to do with Unicode and Perl ?
thanks for taking the time out to help a complete newbie.. I do appreciate it..