1.) Click the Toolbar's wrench icon.
2.) On the Tools tab, select (or deselect) the 'Pop-up blocker' checkbox.
3.) Click Save.
If you allow pop-ups on a website, the Pop-up blocker saves your preference for future visits and adds the site to an 'Allowed sites' list. The next time you visit that website, the Pop-up blocker will continue to allow pop-up windows to appear. You can allow or disallow pop-ups by toggling the Pop-up blocker button on and off while on the site.
The Google toolbar has a pop-up blocker that can also cause problems.
1.) Click on the spanner icon on the far right hand side of the Google tool bar
2.) Click tools
3.) Untick the pop-up blocker box and save