It's a long time since I've seen the 'Unable to find a perl 5' warning, and I've just been googling to refresh my memory. When I did last see it (on Win32), it turned out to be something that needed to be fixed. One fix was to edit the Makefile.PL to inlude 'PERL' => "$^X", in the 'WriteMakefile()' section.

I don't know if that's a relevant thing to do in this instance, but it's something you could try. If it does prove effective, I'm sure someone will be able to come up with a better hack. You certainly don't want to have to edit the Makefile.PL every time you build a module :-)

Cheers,
Rob