Thanks for that Rolf. I think I understand the problem a bit better now.

On windows Term::ReadLine::Perl gets loaded. I can't see a way of fixing it in the module itself but working around it is pretty straightforward. I simply print directly to STDOUT instead of the Term OUTs handle which maps to CONOUT$ on Win. You just need to pad your output with a newline to avoid your output appearing on your prompt and it all works.

Cheers