PLEASE HELP! Pop up menu problems

I'm working on a web site in Dreamweaver MX. My pop down menus do not work at all. they either go to a page that cannot be found or when you mouse over them sometimes they do not appear at all. Let me expain what I am doing, this site is not yet on the web. I select a sliced image on my nav bar, then I go to behaviors and choose show pop-up menu. When the next window appears I fill in the text I want to appear on that menu and then I go and choose from my folder where I would like to link it to. Then I click ok and hit the F12 key to see if it works and nothing happens.
Thanks in advance for your help.
Janine