Some digging dredged this up:

http://www.webreference.com/programming/perl/comments/v.910/

So it turned out that the problem was with XML::SAX from 
"perl-XML-SAX-0.14-5", rpm build host "norob.fnal.gov".

I've yet to try their fix (i.e. use XML::Parser)

Yours
Faye

Troy Dawson wrote:
> Hi,
> It looks like you have the Dag repository enabled, and need to send this 
> to their mailling list.  The perl-XML-Simple that we have is
> 
> perl-XML-Simple-2.14-4.fc6
> 
> https://rpmrepo.org/RPMforge
> 
> Troy
> 
> Faye Gibbins wrote:
>> Hi,
>>
>>   A recent update to perl-XML-Simple on SL5 has broken the handling of
>> "&" in XML code.
>>
>> This example:
>>
>> snip---
>> #!/usr/bin/perl
>>
>> use strict;
>> use warnings;
>> use XML::Simple;
>> use Data::Dumper;
>>
>> my %f;
>> $f{'foo'}='&';
>>
>> print XMLout(\%f);
>> print Dumper(XMLin(XMLout(\%f)));
>> snip---
>>
>> used to produce:
>>
>> snip---
>> <opt foo="&amp;" />
>> $VAR1 = {
>>            'foo' => '&'
>>          };
>> snip---
>>
>> Now it produces:
>>
>> snip---
>> <opt foo="&amp;" />
>> could not find ParserDetails.ini in 
>> /usr/lib/perl5/vendor_perl/5.8.8/XML/SAX
>> $VAR1 = {
>>            'foo' => '&amp;'
>>          };
>> snip---
>>
>> This is a problem for our perl handling of our automount maps (which
>> often have "&" at the ends)
>>
>> Has this been reported do people know of the bug? Or have I made an
>> error somewhere, there's nothing obvious in the man page.
>>
>> yours
>> Faye
>>
>> -- 
>> ---------------------------------------------------------
>> Faye Gibbins, Computing Officer (Infrastructure Services)
>>        GeoS KB; Linux, Unix, Security and Networks.
>> Communications Technologist   -  IT  Professionals' Forum
>> Beekeeper  - The Apiary Project, KB -   www.bees.ed.ac.uk
>> ---------------------------------------------------------
>>
>>    I grabbed at spannungsbogen before I knew I wanted it.
>>
>> The University of Edinburgh is a charitable body,
>> registered in Scotland, with registration number SC005336.
> 
> 


-- 
---------------------------------------------------------
Faye Gibbins, Computing Officer (Infrastructure Services)
       GeoS KB; Linux, Unix, Security and Networks.
Communications Technologist   -  IT  Professionals' Forum
Beekeeper  - The Apiary Project, KB -   www.bees.ed.ac.uk
---------------------------------------------------------

   I grabbed at spannungsbogen before I knew I wanted it.

The University of Edinburgh is a charitable body,
registered in Scotland, with registration number SC005336.