Here is the stack trace:
C:/Ruby/lib/ruby/1.8/yaml/rubytypes.rb:6:in to_yaml' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/connect ion_adapters/abstract/quoting.rb:22:inquote’
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/connect
ion_adapters/mysql_adapter.rb:123:in quote' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/base.rb :1305:inquote_bound_value’
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/base.rb
:1287:in replace_bind_variables' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/base.rb :1287:inreplace_bind_variables’
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/base.rb
:1276:in sanitize_sql' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/base.rb :1062:inadd_conditions!’
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/base.rb
:1012:in construct_finder_sql' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/base.rb :924:infind_every’
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/base.rb
:918:in find_initial' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/base.rb :380:infind’
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/validat
ions.rb:528:in validates_uniqueness_of' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/validat ions.rb:302:invalidates_each’
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/validat
ions.rb:299:in validates_each' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/validat ions.rb:794:inrun_validations’
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/validat
ions.rb:788:in run_validations' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/validat ions.rb:752:invalid_without_callbacks’
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/callbac
ks.rb:306:in valid?' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/validat ions.rb:723:insave_without_transactions’
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/transac
tions.rb:126:in save' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/connect ion_adapters/abstract/database_statements.rb:51:intransaction’
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/transac
tions.rb:91:in transaction' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/transac tions.rb:118:intransaction’
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.2/lib/active_record/transac
tions.rb:126:in save' #{RAILS_ROOT}/app/controllers/enrollment_admin_controller.rb:34:insave_global_document’
-e:4