500 Internal Server Error

undefined method `encoding' for nil:NilClass (NoMethodError)

/usr/local/lib/ruby/2.0/erb.rb:597:in `compile'
/usr/local/lib/ruby/2.0/erb.rb:799:in `initialize'
/usr/local/www/tdiary-git/core/tdiary.rb:209:in `new'
/usr/local/www/tdiary-git/core/tdiary.rb:209:in `do_eval_rhtml'
/usr/local/www/tdiary-git/core/tdiary.rb:162:in `eval_rhtml'
/usr/local/www/tdiary-git/core/tdiary.rb:873:in `eval_rhtml'
/usr/local/www/tdiary-git/core/tdiary/dispatcher/index_main.rb:43:in `run'
/usr/local/www/tdiary-git/core/tdiary/dispatcher/index_main.rb:6:in `run'
/usr/local/www/tdiary-git/core/tdiary/dispatcher.rb:21:in `dispatch_cgi'
/usr/local/www/tdiary-git/core/index.rb:36:in `<top (required)>'
/usr/local/lib/ruby/site_ruby/2.0/rubygems/custom_require.rb:36:in `require'
/usr/local/lib/ruby/site_ruby/2.0/rubygems/custom_require.rb:36:in `require'
index.rb:2:in `<main>'