You might have more than one pop-up blocker in place. Which browser are you using, and which security software? Where did you check that the pop-up blocker was turned off?
Also, which email system are you using? (If you're using an email client, such as Outlook Express or Windows Live Mail, pop-ups shouldn't be involved at all. If you're using a web-based system, most email providers don't use pop-ups either; they simply open another tab or window to display the page that is linked to).