Hi oly4auctions,
The only specific component of Internet Explorer 7.0 on Windows Vista that we've noticed has compatibility issues with our site is the Live Toolbar option, however, I can't say with any degree of certainty whether this is accountable for the behavior you are experiencing.
I recommend filing a support request using the appropriate link on our help page, http://www.auctiva.com/free-auction-software-help/help.aspx, and a member of our customer support team will be happy to help you troubleshoot the problem you are experiencing.
-Mike