undefined method `[]' for nil:NilClass (NoMethodError)

(plugin/tlink.rb):140:in `tlink'
/home/inlet/tdiary/tdiary.rb:92:in `join'
/home/inlet/tdiary/tdiary.rb:92:in `safe'
/home/inlet/tdiary/tdiary.rb:697:in `eval_src'
/home/inlet/tdiary/tdiary.rb:1033:in `do_eval_rhtml'
/home/inlet/tdiary/tdiary.rb:975:in `eval_rhtml'
/home/inlet/tdiary/index.rb:73
index.rb:2:in `require'
index.rb:2