Make my CSS/Ajax image gallery cross-browser compatible

I used bits and pieces from a few different scripts to make an Ajax-powered image gallery that uses tabs to toggle between different sets of pictures. Since I use Firefox, I created it to work in Firefox. The problem is now it ONLY works in Firefox, and I'd like your help to make sure it works just as well in IE, Safari and Opera. I'm not sure if the problems are due to the CSS (very likely) or the Ajax (less likely, I think). I don't want any functionality changes... just get it to work! Again, it needs to work in the latest version of all major browsers, such as IE (v7, but hopefully v6 too), Opera (9+) and Safari (3+). Here's an example in action (as I said, you'll need to use Firefox to see it in action.) [login to view URL] And here's a text file containing information about how it's supposed to work: [login to view URL]