I can see all five images with the Google ads below in IE7 and Firefox if I have ActiveX/javascript enabled.
If ActiveX/javascript is disabled I can see four images in IE7 (not the flash image) and no Google ads. In Firefox I can see five images and no Google ads.
Did the computer you were using have ActiveX/javascript enabled?
I can't see a reason why all the images wouldn't show, but I haven't yet looked closely at your code.
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.