Hiki Error

invalid byte sequence in UTF-8 (ArgumentError)
/home/nagato/public_html/hiki/hiki/command.rb:64:in `initialize'
/home/nagato/public_html/hiki.cgi:39:in `new'
/home/nagato/public_html/hiki.cgi:39:in `block in <main>'
/home/nagato/public_html/hiki/hiki/storage.rb:14:in `open_db'
/home/nagato/public_html/hiki.cgi:38:in `<main>'