Hi sandra0357,
Thanks for posting your question here. The "Preview" button on the Auctiva lister page is intended to cause a pop up window to appear, so the first thing I recommend looking into is whether you might have a pop up blocker enabled on your browser or browser toolbar(s) that is blocking the preview from opening.
Most browsers and browser toolbars (including those made by Yahoo and Google) come equipped with pop up blockers that are enabled by default. You can find a number of good resources that go over how to disable common pop up blockers with a quick search of the internet.
If you are unable to find any pop up blockers on your browser or browser toolbar(s) that may be causing the problem, the next thing I recommend trying that may resolve this problem is clearing your browser cache and then closing and reopening your browser.
If you continue to experience the same problem after trying these measures, please contact our customer support team by mousing over the "Help" tab and selecting the "File Support Case" option and we'll be happy to continue working with you on this.
-Mike