500 Internal Server Error

Accept-Charset encoding error (CGI::InvalidEncoding)

/usr/local/rbenv/versions/2.1.4/lib/ruby/2.1.0/cgi/core.rb:676:in `block (2 levels) in initialize_query'
/usr/local/rbenv/versions/2.1.4/lib/ruby/2.1.0/cgi/core.rb:671:in `each'
/usr/local/rbenv/versions/2.1.4/lib/ruby/2.1.0/cgi/core.rb:671:in `block in initialize_query'
/usr/local/rbenv/versions/2.1.4/lib/ruby/2.1.0/cgi/core.rb:670:in `each'
/usr/local/rbenv/versions/2.1.4/lib/ruby/2.1.0/cgi/core.rb:670:in `initialize_query'
/usr/local/rbenv/versions/2.1.4/lib/ruby/2.1.0/cgi/core.rb:828:in `initialize'
/home/tdiary/users/hikazoh/index.rb:27:in `new'
/home/tdiary/users/hikazoh/index.rb:27:in `<main>'