Ad in Google Ad manager (DoubleClick) not showing up in IE

on this site: http://sta开发者_如何学JAVAging.university-bound.com

I am utilizing DoubleClick for Publishers (Google Ad Manager) I have 6 ads as third-party. In most browsers, all show up fine. In IE, however the first one that should be 519x77 in the top dark-gray area (it should say "Questions?" - check it in FF) does not show. I see no difference between this one and the others that are working. Any suggestions would be greatly appreciated.

well, I have solved my problem but I don't understand why it works. An included file (adCreator.js) is in each creative to generate the actual ad image and link. I don't actually use it on my pages - only within the creatives. When I included a link to it in the master page, however, everything started to work. I have theories as to why this fixed it but, to be honest, my theories make no sense.