Why is Mechanize returning "undefined method 'value=' for nil:NilClass" when trying to set a password? - ruby

Question

I wrote a script with Mechanize to scrape some links, which later I will write code to put into an Excel file.
For now I can't authenticate past the first page. I keep getting an undefined method value= for nil:NilClass when attempting to set the password in the form and haven't been able to find any information on it.
I don't even have the method value= in my code so I don't understand what is going on. The code runs fine for the username, but once I enter the password and hit enter I get the error:
users.rb:11:in `block (2 levels) in <main>': undefined method `value=' for nil:NilClass (NoMethodError)
from (eval):23:in `form_with'
from formity_users.rb:7:in `block in <main>'
from /home/codelitt/.rvm/gems/ruby-2.0.0-p247/gems/mechanize-2.7.1/lib/mechanize.rb:433:in `get'
from formity_users.rb:5:in `<main>'
This is my users.rb script:
require 'rubygems'
require 'mechanize'
a = Mechanize.new
a.get('https://www.example.com') do |page|
#Enter information into forms
logged_in = page.form_with(:id => 'frmLogin') do |f|
puts "Username?"
f.field_with(:name => "LoginCommand.EmailAddress").value = gets.chomp
puts "Password?"
f.field_with(:name => "Login.Password").value = gets.chomp
end.click_button
#Click drop down
admin_page = logged_in.click.link_with(:text => /Admin/)
#Click Users and enter user admin section
user_admin = admin_page.click.link_with(:text => /Users/)
#Scrape and print links for now
user_admin.links.each do |link|
text = link.text.strip
next unless text.length > 0
puts text
end
end

Answer 1

I think your error is coming from
f.field_with(:name => "Login.Password")
which seems to be nil. For username, I see that you have specified input name LoginCommand.EmailAddress and for password input name is Login.Password.
I'd expect anybody who has written this markup to use consistent names. Maybe you should look that the underlying html to see you're using correct field names in your code.