我正在使用ruby 1.8.7和rails 2.3.5，当我尝试运行下面的代码时，我收到了这个奇怪的消息“无法复制NilClass”
rr = Node.find(params[:id])
puts rr.inspect
rr.destroy
应用程序打印出有关节点的正确信息，当我尝试在脚本/控制台中执行完全相同的操作时，它工作正常！我不知道发生了什么......
我将我的应用程序升级到rails 2.3.8，但没有运气：（
请帮忙，
编辑：
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:2184:in `dup'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:2184:in `scoped_methods'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:2188:in `current_scoped_methods'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:2178:in `scope'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:1543:in `find_every'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:1505:in `find_initial'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:613:in `find'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/has_one_association.rb:80:in `find_target'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/association_proxy.rb:239:in `load_target'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/association_proxy.rb:112:in `reload'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations.rb:1250:in `acl'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations.rb:1460:in `send'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations.rb:1460:in `has_one_dependent_destroy_for_acl'
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/callbacks.rb:178:in `send'
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/callbacks.rb:178:in `evaluate_method'
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/callbacks.rb:166:in `call'
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/callbacks.rb:93:in `run'
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/callbacks.rb:92:in `each'
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/callbacks.rb:92:in `send'
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/callbacks.rb:92:in `run'
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/callbacks.rb:276:in `run_callbacks'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/callbacks.rb:344:in `callback'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/callbacks.rb:336:in `destroy_without_transactions'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:229:in `send'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:229:in `with_transaction_returning_status'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/database_statements.rb:136:in `transaction'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:182:in `transaction'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:228:in `with_transaction_returning_status'
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:192:in `destroy'
/home/wael/public_html/app/models/node.rb:355:in `destroy'
Wa'el