in reply to How to scraper ASP websites
Always use strict; and use warnings;. You don't define $__EVENTVALIDATION and $__VIEWSTATE that's why your code send empty values to the target site.
These values are located in the HTML form you receive from the target site and WWW::Mechanize will send these values automatically for you.
Also I'm sure that WWW::Mechanize::Firefox will work for such site (of course you must don't touch __VIEWSTATE and __VIEWSTATE).