The entire process works in three stages:

Perl -> Csound -> Soundfile

Perl is the top level in this chain. It's where I compose the piece. Rain.pl generates Rain.sco. Csound is a synthesis language. Csound takes Rain.sco and Rain.orc and generates a soundfile.

As for the errors, I'm not getting those on my machine. But I take full responsibility for anything broken in my code. :)