ulimit -s 3276 http://johnwilger.com/2007/11/accessing-original-scope-from-ruby.htmlsays that “when you run define_method you can accidentally create infinite loops”–which this one is doing, as you can see  

exceptionstack level too deepSystemStackError: stack level too deep
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/base.rb:1983:in `=='
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/base.rb:1983:in `==='
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/base.rb:1983:in `convert_number_column_value'
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/base.rb:1973:in `write_attribute'
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/attribute_methods.rb:67:in `attribute='
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/base.rb:1855:in `__send__'
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/base.rb:1855:in `method_missing'
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/base.rb:1672:in `send'
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/base.rb:1672:in `attributes='
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/base.rb:1671:in `each'
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/base.rb:1671:in `attributes='
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/base.rb:1505:in `initialize_without_callbacks'
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/callbacks.rb:225:in `initialize'
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/base.rb:449:in `new'
	from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/base.rb:449:in `create'
	from ./db/add_single_zips.rb:3918
	from ./db/add_single_zips.rb:3908:in `each_line'
	from ./db/add_single_zips.rb:3908
	from ./db/add_single_zips.rb:3888:in `each_line'
	from ./db/add_single_zips.rb:3888
	from /opt/local/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:493:in `load'
	from /opt/local/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:493:in `load'
	from /opt/local/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:345:in `new_constants_in'
	from /opt/local/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:493:in `load'
	from (irb):9>> exit

So an easy way around it is to make sure those methods are defined already (like attributes=). Make a normal one. Save it. Maybe?