The most likely cause is that you have a pop-up blocker installed on your browser that’s preventing the new window from being visible.

Here’s how to disable it:
•       Click on the Google Toolbar’s “Settings” drop-down, then select “Options”.
•       Click on the “More” tab.
•       Under the “Popup Blocker” section, uncheck the “Popups okay” and “Play a sound” boxes (see below).

•       Click the “OK” button to close the “Toolbar Options” dialog.