Javascript Rollover Problem

I am using a Javascript rollover on my left bar for navigation. I preload my images for seamless rollovers. It works fine in IE, but in Netscape (6.1) there is a delay in the rollover. This causes an ugly flash effect when rolling over. The odd thing is that if I hit the Home link from the Home page, it works fine until I hit refresh or reload the page. Any ideas? Thanks!