shakuni,
Ok, you have been given a hint (Using WWW::Selenium To Test Or Automate An Ajax Website). Why don't you start by saying what you have and have not accomplished.

• Successfully Loging
• Click the "tasks" link
• Find the tasks pop-up window
• Fetch the HTML of the tasks pop-up window
• Parse the HTML to the desired end

In other words - show some effort and give us something more to go on than "it doesn't work".