Hiki Error

invalid byte sequence in UTF-8 (ArgumentError)
/usr/local/hiki/hiki/lib/hiki/command.rb:65:in `initialize'
/usr/local/hiki/hiki/hiki.cgi:35:in `new'
/usr/local/hiki/hiki/hiki.cgi:35:in `block in <top (required)>'
/usr/local/hiki/hiki/lib/hiki/storage/base.rb:13:in `open_db'
/usr/local/hiki/hiki/hiki.cgi:34:in `<top (required)>'
/home/nay/public_html/hiki.cgi:3:in `load'
/home/nay/public_html/hiki.cgi:3:in `<main>'