mkdir("c:\\season1\\unearthly\\ep1\\caps");
it will only work if directory c:\season1\unearthly\ep1 already exists.
File::Path::make_path() will create a directory and any necessary ancestor directories (must use mkpath() instead on Perl 5.10 and possibly other versions earlier than 5.14).
NB it's File::Path:: not File::Path-> - the latter will give you a misleading error "mkdir File::.: Invalid argument; The filename, directory name, or volume label syntax is incorrect" .