net.roth? I don't think so :)

Besides,
C:\> GET http://www.roth.net/perl/packages/Win32-Message.ppd
<SOFTPKG NAME="Win32-Message" VERSION="0,2001,12,24"> <TITLE>Win32::Message</TITLE>
<ABSTRACT>The Win32::Message extension for Win32 X86. Manages sending network messages.</ABSTRACT>
<AUTHOR>Roth Consulting (http://www.roth.net/)</AUTHOR> <IMPLEMENTATION>
<OS NAME="MSWin32" />
<ARCHITECTURE NAME="MSWin32-x86-object" />
<CODEBASE HREF="http://www.roth.net/perl/packages/x86/Win32/Message.tar.gz" />
</IMPLEMENTATION>
<IMPLEMENTATION>
<OS NAME="MSWin32" />
<ARCHITECTURE NAME="MSWin32-x86-multi-thread" />
<CODEBASE HREF="http://www.roth.net/perl/packages/x86/Win32/Message_5006.tar.gz" />
</IMPLEMENTATION>
</SOFTPKG>

The 1st architecture indicates perl-5.5.x, the 2nd one indicates perl-5.6.x.
What you're looking for is <ARCHITECTURE NAME="MSWin32-x86-multi-thread-5.8" />