Cant upload file with mechanize

Ruby
1

hy
i try to upload a file with mechanize but i dont understand why i cant
??
I try with two differents params name and id but each time i get an
error.

*Code: *
agent = Mechanize.new{ |a| a.log = Logger.new(“Mechanize.log”) }
agent.read_timeout = 60
agent.user_agent_alias = ‘Linux Mozilla’
{
‘Linux Mozilla’ => ‘Mozilla/5.0 (X11; U; Linux i686; en-US;
rv:1.4) Gecko/20030624’,
‘Linux Firefox’ => ‘Mozilla/5.0 (X11; U; Linux i686; en-US;
rv:1.9.2.1) Gecko/20100122 firefox/3.6.1’
}

agent.get(“http://XXXX”)

     form = agent.page.parser.css('form')[0]
         agent.page.forms[0]["login"] = "login"
         agent.page.forms[0]["password"] = "password"
       res = agent.page.forms[0].submit

 #uploadFile = agent.click(res.link_with(:name => "file"))
 uploadFile = agent.click(res.link_with(:id => "filepc"))

Error: *with id *
/usr/local/rvm/gems/ruby-2.1.3/gems/mechanize-2.7.3/lib/mechanize.rb:354:in
click': undefined method []’ for nil:NilClass (NoMethodError)
from mechanize.rb:33:in `’

Error: with name
(eval):14:in block (2 levels) in links_with': undefined method name’
for
#<Mechanize::Page::Link "

*HTML code *: