cant able to migrate

E:\instant_college\db\sample>rake db:migrate
(in E:/instan_college)
rake aborted!
undefined method `tap' for
[ActiveRecord::Associations::AssociationCollection]:A
rray

i installed ruby 1.8.6 and rails 2.3.8.. when i tried to migrate , i got
this error.. somebody help me!

show what you have in your models, it seems like you have a typo