Hiki Error

invalid byte sequence in EUC-JP (ArgumentError)
/home/arton/public_html/hiki/hiki/storage.rb:66:in `index'
/home/arton/public_html/hiki/hiki/storage.rb:66:in `block (2 levels) in search'
/home/arton/public_html/hiki/hiki/storage.rb:62:in `each'
/home/arton/public_html/hiki/hiki/storage.rb:62:in `block in search'
/home/arton/public_html/hiki/hiki/storage.rb:55:in `reverse_each'
/home/arton/public_html/hiki/hiki/storage.rb:55:in `search'
/home/arton/public_html/hiki/hiki/command.rb:458:in `cmd_search'
/home/arton/public_html/hiki/hiki/command.rb:122:in `block in dispatch'
/usr/local/lib/ruby/3.3.0/timeout.rb:186:in `block in timeout'
/usr/local/lib/ruby/3.3.0/timeout.rb:41:in `handle_timeout'
/usr/local/lib/ruby/3.3.0/timeout.rb:195:in `timeout'
/home/arton/public_html/hiki/hiki/command.rb:95:in `dispatch'
/home/arton/public_html/hiki/hiki.cgi:52:in `block in <top (required)>'
/home/arton/public_html/hiki/hiki/storage.rb:14:in `open_db'
/home/arton/public_html/hiki/hiki.cgi:50:in `<top (required)>'
/home/arton/public_html/collabo/backyard/index.cgi:8:in `load'
/home/arton/public_html/collabo/backyard/index.cgi:8:in `<main>'