undefined method `empty?' for -279519369:Fixnum (NoMethodError)

/home/mini/ruby/lib/ruby/1.8/erb.rb:417:in `scan'
/home/mini/ruby/lib/ruby/1.8/erb.rb:524:in `compile'
/home/mini/ruby/lib/ruby/1.8/erb.rb:690:in `initialize'
/usr/local/httpd/htdocs/mini/diary/tdiary.rb:335:in `eval_rhtml'
(erb):31:in `do_eval_rhtml'
/usr/local/httpd/htdocs/mini/diary/tdiary.rb:1457:in `each_day'
/usr/local/httpd/htdocs/mini/diary/tdiary.rb:1454:in `each_day'
(erb):30:in `do_eval_rhtml'
/usr/local/httpd/htdocs/mini/diary/tdiary.rb:898:in `do_eval_rhtml'
/usr/local/httpd/htdocs/mini/diary/tdiary.rb:854:in `eval_rhtml'
/usr/local/httpd/htdocs/mini/diary/index.rb:71