I am having problems with the behavior (show popup menu) to show up. I have already tried changing the browser info. I am trying to have underlinks that popup when you mouseover the button or link.

I had so much trouble creating popup menus in Dreamweaver that I finally gave up -- they would work fine in IE but not in Firefox, among other problems. I ended up paying for and downloading AllWebMenus (www.likno.com).  It's very easy to use and highly customizable, and integrates right into Dreamweaver. I'm extremely happy with it. The expense (about $60) was worth it to me because I've used it for several sites, but there are probably less expensive -- and perhaps free -- programs out there.

I wish I had back all the time I spent trying to make popup menus in Dreamweaver -- my advice would be to abandon the effort and find an alternative way to get it done.