can't convert Fixnum into String (TypeError)

/home/mini/ruby/lib/ruby/1.8/erb.rb:504:in `<<'
/home/mini/ruby/lib/ruby/1.8/erb.rb:504:in `cr'
/home/mini/ruby/lib/ruby/1.8/erb.rb:541:in `compile'
/home/mini/ruby/lib/ruby/1.8/erb.rb:418: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:899: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