For security reasons you are not allowed to open more than one Browser Window or New Tab for this domain at Same Machine.
If yoy want to open more than one Browser Window for this domain at Same Machine follow the instructions below.

For (Internet Explorer)::  File->New Session
For (Google Chrome):: Browser Menu::Incognito Window (Ctrl+Shift+N)
For (Mozilla Firefox):: Browser Menu::New Private Window (Ctrl+Shift+P)
or
“ Clear your Browsing History and Login again using your Application Number and password “