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

/usr/local/ruby-2.0/lib/ruby/2.0.0/erb.rb:597:in `compile'
/usr/local/ruby-2.0/lib/ruby/2.0.0/erb.rb:799:in `initialize'
/home/tdiary/tdiary/tdiary-core/tdiary/base.rb:131:in `new'
/home/tdiary/tdiary/tdiary-core/tdiary/base.rb:131:in `erb_src'
/home/tdiary/tdiary/tdiary-core/tdiary/base.rb:59:in `do_eval_rhtml'
/home/tdiary/tdiary/tdiary-core/tdiary/base.rb:30:in `eval_rhtml'
/home/tdiary/users/nabeken/search.rb:257:in `<main>'