NoMethodError in User sessionsController#create - Authlogic

I am getting this type of error while connecting my application with
Please help me to fin solution for my problem

NoMethodError in SessionsController#new

You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.+

This is nothing to do with the original subject of this thread. I
suggest starting a new thread with an appropriate subject. First
however examine the error message carefully and try and work out what
it means. There should be a stack trace showing which line the error
appeared on.