With regard to the Win32 Perl that is currently distributed with the XAMPP project 1.7.3:
After receiving two questions recently about the source of this distribution, I checked with the project leader Oswald Seidler. He has confirmed my basic understanding, which is that Carsten Weidmann compiled the perl.org source files himself to be included with XAMPP. He is also the person who modified batch/script files for Perl that are included. My understanding is that this is a Win32 only thread safe compilation.
For those who you wish to work with Perl on XAMPP, I recommend you opening the batch files and reading through them as they are fairly well documented. I have tested both ppm.bat, and cpan.bat; as far as I can tell, they both work correctly.
I'm going to do a few more experiments with cpan.bat, as the test I chose had dependency errors that would be time-consuming and pointless to resolve for my server. Cpan.bat did fetch the code, build, make, install and test - and reported errors, so I expect it is working correctly.
I can confirm that I was able to install directly Class-Accessor with ppm.bat
C:\xampp\perl\bin>ppm install Class-Accessor
Installing package 'Class-Accessor'...
Bytes transferred: 22554
and ~tada~ it appears on my Perlinfo page:
Class::Accessor 0.34 Automated accessor generation
Class::Accessor::Fast 0.34 Faster, but less expandable, accessors
Class::Accessor::Faster 0.34 Even faster, but less expandable, accessors
Sooo - at least the 1.7.3 version seems to be working right...