End-of-File Error occured at <except.c>:79 in xraise

On an average I get this error twice or thrice a week. After I rebuild
the index Event.rebuild_index it works fine.

I’m a bit puzzled by this behavior. Why does this happen? I am using
AAF.

End-of-File Error occured at <except.c>:79 in xraise
Error occured in store.c:216 - is_refill
current pos = 301, file length = 301

/usr/local/lib/ruby/site_ruby/1.8/ferret/index.rb:517:in close' /usr/local/lib/ruby/site_ruby/1.8/ferret/index.rb:517:inflush’
/usr/local/lib/ruby/1.8/monitor.rb:229:in synchronize' /usr/local/lib/ruby/site_ruby/1.8/ferret/index.rb:514:inflush’

/usr/local/lib/ruby/site_ruby/1.8/ferret/index.rb:280:in <<' /usr/local/lib/ruby/1.8/monitor.rb:229:insynchronize’
/usr/local/lib/ruby/site_ruby/1.8/ferret/index.rb:252:in <<' #{RAILS_ROOT}/vendor/plugins/acts_as_ferret/lib/instance_methods.rb:85:inferret_update’

/usr/local/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/callbacks.rb:344:in
callback' /usr/local/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/callbacks.rb:341:incallback’
/usr/local/lib/ruby/gems/1.8/gems/activerecord-
1.14.4/lib/active_record/callbacks.rb:279:in update_without_timestamps' /usr/local/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/timestamp.rb:39:inupdate’
/usr/local/lib/ruby/gems/1.8/gems/activerecord-
1.14.4/lib/active_record/base.rb:1718:in
create_or_update_without_callbacks' /usr/local/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/callbacks.rb:253:increate_or_update’
/usr/local/lib/ruby/gems/1.8/gems/activerecord-
1.14.4/lib/active_record/base.rb:1392:in save_without_validation' /usr/local/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/validations.rb:736:insave_without_transactions’
/usr/local/lib/ruby/gems/1.8/gems/activerecord-
1.14.4/lib/active_record/transactions.rb:126:in save' /usr/local/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/connection_adapters/abstract/database_statements.rb:51:intransaction’
/usr/local/lib/ruby/gems/1.8/gems/activerecord-
1.14.4/lib/active_record/transactions.rb:91:in transaction' /usr/local/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/transactions.rb:118:intransaction’
/usr/local/lib/ruby/gems/1.8/gems/activerecord-
1.14.4/lib/active_record/transactions.rb:126:in save' /usr/local/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/base.rb:1398:insave_without_validation!’
/usr/local/lib/ruby/gems/1.8/gems/activerecord-
1.14.4/lib/active_record/validations.rb:746:in save!' #{RAILS_ROOT}/app/controllers/home_controller.rb:33:inevent_info’