I think I have fixed this problem.
First,type $ bundle show devise_openid_authenticatable
to see where the bundled gem is installed.
e.g. /Users/YOURNAME/.bundle/ruby/1.8/gems/devise_openid_authenticatable-1.0.0.alpha2
cd in this directory and modify /lib/devise_openid_authenticatable/schema.rb
from apply_schema :identity_url, String
to apply_devise_schema :identity_url, String
That's OK!
VvDPzZ
2010-07-07 06:57:01