Hiki Error

invalid byte sequence in UTF-8 (ArgumentError)
/usr/local/hiki/hiki/lib/hiki/util.rb:169:in `split'
/usr/local/hiki/hiki/lib/hiki/util.rb:169:in `unified_diff'
/usr/local/hiki/hiki/lib/hiki/command.rb:377:in `rescue in cmd_diff'
/usr/local/hiki/hiki/lib/hiki/command.rb:372:in `cmd_diff'
/usr/local/hiki/hiki/lib/hiki/command.rb:131:in `block in dispatch'
/usr/local/rbenv/versions/2.6.5/lib/ruby/2.6.0/timeout.rb:93:in `block in timeout'
/usr/local/rbenv/versions/2.6.5/lib/ruby/2.6.0/timeout.rb:33:in `block in catch'
/usr/local/rbenv/versions/2.6.5/lib/ruby/2.6.0/timeout.rb:33:in `catch'
/usr/local/rbenv/versions/2.6.5/lib/ruby/2.6.0/timeout.rb:33:in `catch'
/usr/local/rbenv/versions/2.6.5/lib/ruby/2.6.0/timeout.rb:108:in `timeout'
/usr/local/hiki/hiki/lib/hiki/command.rb:104:in `dispatch'
/usr/local/hiki/hiki/hiki.cgi:36: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>'