Hi Southern Girl,
The only component of Vista that is known to cause conflicts with Auctiva under some circumstances is the Live Toolbar, which I believe is installed by default. It would definitely be worth a shot to uninstall that component to see if doing so resolves this problem for you. Another troublesome one is the My Web Search browser add-on by Fun Web Products, but that is not specifically associated with Vista. Otherwise, there are a number of possible causes for this behavior.
If you continue to experience this problem, I recommend contacting our customer support team using the appropriate link on our help page:
http://www.auctiva.com/free-auction-software-help/help.aspx-Mike