"If it has something to do with $^X"

$^X has no issues on windows. As Corion mentions the failure relates to not catering for windows quoting. You said this module "is extremely useful for rapid prototyping", the alternatives listed in CGI::Alternatives are a better choice in this (and in fact every) respect , because it's trivial to rapidly prototype and scale up without throwing away the code, which you'd be doing if you went down your recommended path.