Read-only file system - "/home/groups/z/zo/zodiac/diary/200907" (Errno::EROFS)

/home/groups/z/zo/zodiac/ruby/lib/ruby/1.6/pstore.rb:92:in `open'
/home/groups/z/zo/zodiac/ruby/lib/ruby/1.6/pstore.rb:92:in `transaction'
/home/groups/z/zo/zodiac/htdocs/diary/tdiary.rb:545:in `transaction'
/home/groups/z/zo/zodiac/htdocs/diary/tdiary.rb:1044:in `initialize'
/home/groups/z/zo/zodiac/htdocs/diary/index.rb:29:in `new'
/home/groups/z/zo/zodiac/htdocs/diary/index.rb:29