Hiki Error

invalid byte sequence in UTF-8 (ArgumentError)
/usr/share/hiki/hiki/command.rb:64:in `initialize'
/usr/share/hiki/hiki.cgi:39:in `new'
/usr/share/hiki/hiki.cgi:39:in `block in <top (required)>'
/usr/share/hiki/hiki/storage.rb:14:in `open_db'
/usr/share/hiki/hiki.cgi:38:in `<top (required)>'
/home/decade_sec/public_html/wiki/open/hiki.cgi:4:in `load'
/home/decade_sec/public_html/wiki/open/hiki.cgi:4:in `<main>'