BEGIN {
   # Wrong, and the cause of the OP's problem. See my reply to the OP.
   binmode(STDIN, ':encoding(UTF-8)');

   # Necessary to encode the returned HTML.
   binmode(STDOUT, ':encoding(UTF-8)');

   # Necessary to encode error messages for the log.
   binmode(STDERR, ':encoding(UTF-8)');
}